UNIX for Intermediate Users
Developed by:
User Liaison Section, D-7131
[Name and numbers removed at author's request]
Revision Date:
TABLE OF CONTENTS
I. INTRODUCTION........................................................................ ii
A. Audience..................................................................... ii
B. Course Objectives............................................................ ii
C. Course Handout Conventions...................................................iii
1. THE FILE CALLED .profile AND PROCESSES.............................................. 1
1.1 HOME........................................................................ 1
1.2 PATH........................................................................ 2
1.3 INGRES Environment Variables................................................ 2
1.4 ING_HOME.................................................................... 3
1.5 TERM_INGRES................................................................. 3
1.6 ING_EDIT.................................................................... 3
1.7 Processes................................................................... 4
1.8 Executing a Command......................................................... 4
1.9 Process Identification...................................................... 5
1.10 Interrupt Handling......................................................... 7
2. COMPILING "C" PROGRAMS............................................................... 10
2.1 "C": Sample Program with a Main and Two Functions
in One ............................................................ 10
2.2 "C": Compiling a Program.................................................... 12
2.3 "C": Renaming the Executable Module......................................... 13
2.4 "C": Giving a Name to the Output File....................................... 14
2.5 "C": Producing an Assembly Listing.......................................... 15
2.6 "C": Main and Two Functions in Three Separate
Source Files.............................................................. 16
2.7 "C": Compiling but Not Producing an Executable
Module.................................................................... 17
3. COMPILING FORTRAN PROGRAMS......................................................... 18
3.1 FORTRAN: Sample Program a Main and Two
Subroutines............................................................... 18
3.2 FORTRAN: Compiling a Program................................................ 19
3.3 FORTRAN: Renaming the Executable Module..................................... 20
3.4 FORTRAN: Giving a Name to the Output File................................... 21
3.5 FORTRAN: Producing an Assembly Listing...................................... 22
3.6 FORTRAN: Main and Two Subroutines in Three
Separate Source Files........................................ 23
3.7 FORTRAN: Compiling But Not Producing an Executable
Module.................................................................... 24
3.8 FORTRAN: Compiling Object Files to Produce an
Executable Module....................................... 25
4. COMPILING COBOL PROGRAMS............................................................ 26
4.1 COBOL: Sample Program with a Main and Two
Subroutines............................................................... 26
4.2 COBOL: Compiling a Program.................................................. 27
4.3 COBOL: Running a Program.................................................... 28
Workshop 2-4..................................................................... 30
5. UNIX TOOLS.......................................................................... 34
5.1 The make Utility............................................................ 34
p: A Pattern Matching Filter............................................................ 37
5.2.1 More on Regular Expressions........................................ 38
5.2.2 Closure............................................................ 42
5.2.3 Some Nice grep Options ................................ 43
5.2.4 Summary of Regular Expression Characters........................... 44
5.3 sed: Edit a File to Standard Output......................................... 45
5.4 awk: A Pattern Matching Programming Language................................ 49
5.5 sort: Sort a File........................................................... 53
5.6 Archiver and Library Maintainer............................................. 56
5.7 Creating an Archive File with Object Modules................................ 57
5.8 Verifying the Contents of the Archive File.................................. 57
5.9 Removing Duplicate Object Files............................................. 58
5.10 Compiling Main and Archive Files........................................... 58
Workshop 5....................................................................... 59
6. UNIX UTILITIES PART I - DISPLAY AND MANIPULATE FILES................................ 63
7. UNIX UTILITIES PART II - DISPLAY AND ALTER STAUTS................................... 73
8. UNIX UTILITIES PART III - MISCELLANEOUS............................................. 85
9. ADVANCED FEATURES OF FTP............................................................ 90
9.1 Initializing FTP on UMAX.................................................... 91
9.2 Multiple File Transfers..................................................... 92
9.3 Auto Login Feature.......................................................... 93
9.4 Macros...................................................................... 95
9.5 Filename Translation........................................................ 96
9.6 Aborting Transfers.......................................................... 97
9.7 More Remote Computer Commands............................................... 98
Workshop 10...................................................................... 99
APPENDIX A - sh.........................................................................101
APPENDIX B - ftp........................................................................116
APPENDIX C - C Compiler.................................................................128
APPENDIX D - FORTRAN Compiler...........................................................137
APPENDIX E - lint.......................................................................147
APPENDIX F - cb.........................................................................151
APPENDIX G - ar.........................................................................152
INDEX...................................................................................157
I. INTRODUCTION
A. Audience
This course is for individuals who need to use utilities and
advanced features of the UNIX operating system.
B. Course Objectives
Upon successful completion of this course the student will be
able to:
1. Compile C, FORTRAN, and COBOL programs.
2. Create processes to run in the background
3. Use advanced features of FTP such as: multiple file
transfers, auto logins, macros, globbing, filename
translation, aborting transfers, and other remote
computer commands.
4. Use UNIX utility programs such as grep, sed, awk, sort,
and others.
5. Use the make utility.
6. Understand processes, including structure, executing a
command, process identification, exit status, plus .
(dot) and exec processing.
C. Course Handout Conventions
There are several conventions used in this handout for
consistency and easier interpretation:
1. Samples of actual terminal sessions are single-lined
boxed.
2. User entries are shown in bold print and are
underlined.
exit
3. All keyboard functions in the text will be bold.
(Ret) Backspace
Tab Ctrl-F6
Print (Shift-F7) Go to DOS (1)
NOTE: (Ret) indicates the Return or Enter key
located above the right Shift key.
4. Examples of user entries not showing the computer's
response are in dotted-lined boxes.
5. Command formats are double-lined boxed.
6. Three dots either in vertical or horizontal alignment
mean continuation or that data is missing from diagram.
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 3
3 Multimax, Nanobus, and UMAX are trademarks of 3
3 Encore Computer Corporation. 3
3 3
3 3
3 Annex is a trademark of XYLOGICS, Inc. 3
3 3
3 3
3 UNIX and Teletype are registered trademarks of 3
3 AT&T Bell Laboratories 3
3 3
3 3
3 Ethernet is a trademark of Xerox Corporation 3
3 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
1. UNIX PROCESSES AND A FILE CALLED .profile
1.1 Processes
A process is the execution of a command by UNIX. Processes can
also be executed by the operating system itself. Like the file
structure, the process structure is hierarchical. It contains
parents, children, and even a root. A parent can fork (or spawn)
a child process. That child can, in turn, fork other processes.
The first thing the operating system does to begin execution is
to create a single process, PID number 1. PID stands for Process
Identification. This process will hold the same position as the
root directory in the file structure. This process is the
ancestor to all processes that each user works with. It forks a
process for each terminal. Each one of these processes becomes a
Shell process when the user logs in.
1.2 Process Identification
The UNIX operating system assigns a unique process identification
number (PID) to each process. It will keep the same PID as long
as the process is in existence. During one session, the same
process is always executing the login Shell. When you execute
another command, a new process is forked and a new PID is
assigned to that process. When that child process is finished,
you are returned to the login process, which is running the
Shell, and that parent process has the same PID as when you
logged in.
The Shell stores the PID in Shell variable called $$. The PID
can also be shown with the process status (ps) command. The
format for ps is as follows:
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? Command Format: ps [options] ?
? ?
? See on-line manual for options ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
With no options given the ps command will give you certain
information about processes associated with the controlling
terminal. The output consists of a short listing containing the
process id, terminal id, cumulative execution time, and the
command name. Otherwise, options will control the display.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $echo $$ 3
3 8347 3
3 $ps 3
3 PID TTY TIME COMMAND 3
3 8347 rt021a0 0:03 ksh 3
3 8376 rt021a0 0:06 ps 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
The PID numbers of the Shell are the same in the sample session
because the Shell will substitute its own PID number for $$.
The Shell makes the substitution before it forks a new process to
execute the echo command. Therefore, echo will display the PID
number of the process that called it, not the PID of the process
that is executing it.
The -l option will display more information about the processes.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $ps -l 3
3 F S UID PID PPID C PRI NI ADDR SZ WCHAN TTY TIME COMD 3
3 f0000 S 115 8347 309 2 30 20 1009000 140 94014 rt021a0 0:03 ksh 3
3 f0000 O 115 8386 8347 16 68 20 1308000 72 rt021a0 0:01 ps 3
3 $ps -l 3
3 F S UID PID PPID C PRI NI ADDR SZ WCHAN TTY TIME COMD 3
3 f0000 S 115 8347 309 1 30 20 1009000 140 94014 rt021a0 0:03 ksh 3
3 f0000 O 115 8387 8347 26 73 20 1146000 72 rt021a0 0:01 ps 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
1.3 Executing a Command
When you give a command to the Shell, it will fork a process to
execute the command. While the child process is executing the
command, the parent will go to sleep. Sleeping means that the
process will not use any CPU time. It remains inactive until it
is awakened. When the child process has finished executing the
command, it dies. The parent process, which is running the
Shell, wakes up and prompts you for another command.
When you request a process to run in the background (by ending
the command line with an ampersand character (&), the Shell forks
a child process that is allowed to run to completion. The parent
process will report the PID of the child process and then prompt
you for another command. The child and parent are now
independent processes.
1.4 The . (dot) and exec Commands
There are two ways to execute a program without forking a new
process. The . (dot) command will execute the script as part of
the current process. When the new script has finished executing,
the current process will continue to execute the original script.
The exec command will execute the new script in place of
(overlays) the original script and never returns to the original
script.
The . (dot) command will not execute compiled files (binary) and it does not require execute
permission on the script file that is being executed. The exec command does require access
permission to either a binary program or a shell script.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $ls -l prog2 3
3 -rw-r--r-- 1 teacher class 22 Jan 18 10:30 prog2 3
3 $cat prog2 3
3 echo 'prog2 PID =' $$ 3
3 $cat dot_example 3
3 echo $0 'PID=' $$ 3
3 . prog2 3
3 echo 'This line is executed' 3
3 $dot_example 3
3 dot_example PID= 6942 3
3 prog2 PID = 6942 3
3 This line is executed 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
The exec command will overlay the sh and control will never return to the calling script.
Let's look at another example with a call to prog2 using exec instead of . (dot):
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $ls -l prog2 3
3 -rwxr-xr-x 1 teacher class 22 Jan 18 10:30 prog2 3
3 $cat prog2 3
3 echo 'prog2 PID =' $$ 3
3 $cat exec_example 3
3 echo $0 'PID=' $$ 3
3 exec prog2 3
3 echo 'This line is never executed' 3
3 $exec_example 3
3 exec_example PID= 6950 3
3 prog2 PID = 6950 3
3 $ 3
3 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
Background Processing
When a program is running in background you do not have to wait for it to finish before
starting another program. This is useful because you can start long/large jobs and then
continue to do another task on your terminal.
To run a program in background simply type an ampersand character (&) at the end of the
command line before the (Ret) key. The Shell will return the PID of the background process
and then give you another system prompt.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $ls -l | lp & 3
3 [1] 21334 3
3 $request id is mt_600-2736 (standard input) 3
3 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
If the background task sends output to standard output and you fail to redirect it, the
output will appear on your terminal even if you are running another program at the time.
It is necessary to use the kill command to stop a process that is running in background the
(DEL) key or its equivalent will not work.
Exit Status
When a process stops executing for any reason, it will return an exit status to the parent
process. This exit status is also referred to as a condition code or return code.The Shell
stores the exit status in a Shell variable called $?. By convention, a non-zero exit status
means that it has a false value and the command failed. On the other hand, a zero status
indicates true and the command was successful.
It is possible for you to specify the exit status when you exit a script. This is done by
specifying the number to be used as the exit status using the exit command. The following
script is an example:
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $cat exit_example 3
3 echo 'This program returns an exit status' 3
3 echo 'of 7.' 3
3 exit 7 3
3 $exit_example 3
3 This program returns an exit status 3
3 of 7. 3
3 $echo $? 3
3 7 3
3 $echo $? 3
3 0 3
3 $ 3
3 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
This script will display the message and then exit with an exit code of 7. The exit status
is stored in the Shell variable called $?. The second echo command above displays the exit
status of the first echo command. Since it completed successfully it has a value of zero.
1.4 Interrupt Handling
A signal is a report to a process about a condition. UNIX uses
these signals to report bad system calls, broken pipes, illegal
instructions, and other conditions. There are three signals that
are useful when programming in the Shell. They are the terminal
interrupt signal (number 2), the kill signal (number 9) and the
software termination signal (number 15).
You can use the trap command to capture a signal and then take
whatever action you specify. It can close files or finish other
processing that needs to be done, display a message, terminate
execution immediately, or ignore the signal.
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? Command Format: trap ['commands'] signal_numbers ?
? ?
? See online man pages for details ?
? ?
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The signal_numbers are the numbers corresponding to the signals
that will be trapped by the trap command. There must be at least
one number present. The 'commands' portion of the command is
optional. If it is not present, the command resets the trap to
its initial condition, which is to exit the program. When the
commands is present the Shell executes the commands when it
catches one of the signals. After executing the commands, the
Shell continues executing the script where it left off.
You can interrupt a program you are running in the foreground by
pressing the Delete key. When you press this key a signal
(number 2), a terminal interrupt, to the program. The Shell will
terminate the execution of the program if the program does not
trap the signal. The following example demonstrates the trap
command that will trap the signal and return an exit status of 1.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $cat inter 3
3 trap 'echo PROGRAM INTERRUPTED; exit 1' 2 3
3 while (true) 3
3 do 3
3 echo 'Program running' 3
3 done 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
The first line of inter sets up a trap for signal number 2, the
terminal interrupt. When the signal is caught, the Shell will
execute the commands between the two single quote marks. In this
example, the echo command will display PROGRAM INTERRUPTED. The
exit command will then return control to the Shell and a system
prompt is displayed. If the exit were missing, control would
revert to the while loop after displaying the message.
You can send a software termination to a background process using
the kill command without a signal number. However, a trap
command can be set to catch this signal (number 15). A kill
signal can be sent to kill a process with a signal number 9 and
the Shell cannot catch a kill signal.
The file called .profile
The BourneShell declares and initializes variables that determine
such things as your home directory, what directories the Shell
will look in when you give commands, how often to look for mail,
your system prompt, and many other things. We will look at some
of these Shell variables and their functions. You can assign new
values to these variables from the command line or by executing
the contents of a file called .profile. The BourneShell executes
the commands in this file in the same environment as the Shell
each time the user logs in. The .profile must be in the user'
home directory. Each user has a different .profile. It usually
specifies the terminal type and establishes terminal
characteristics and other housekeeping functions as required by
the user.
1.5 HOME
The first BourneShell variable that we will look at is the HOME
variable. By default, the home directory is the current working
directory after you login. The system administrator determines
your home directory when you establish an account and places that
information in the /etc/passwd file. When you login, the
BourneShell gets that pathname and assigns it to the HOME
variable.
When you enter a cd command with no argument, the utility takes
the name of the directory from the HOME variable and makes it the
current working directory. If you change the HOME variable to
another directory pathname, the utility will make the new
directory the current working directory.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $echo $HOME 3
3 /user0/rharding 3
3 $cd 3
3 $pwd 3
3 /user0/rharding 3
3 $HOME=/user0/rharding/eng 3
3 $cd 3
3 $pwd 3
3 /user0/rharding/eng 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
This example shows how the value of the HOME variable affects the
cd utility. The cd command will use the value of the HOME
variable as the pathname for the current working directory.
1.6 PATH
This BourneShell variable will describe the directories that will
be searched looking for the program that you want to execute.
The BourneShell looks in several directories for a file that has
the same name as the command that you entered. The PATH variable
controls this search path. Normally, the first directory
searched is the current working directory. If the program is not
found, the search continues in the /bin and then the /usr/bin
directory. Generally, these directories contain executable
programs. If the program is not found in one of these
directories, the BourneShell reports that the program can't be
found (or executed).
The PATH variable lists the pathnames in the order in which the
search will proceed. The pathnames are separated by a colon (:).
If nothing (null string) precedes the colon, that indicates to
start the search at the current working directory.
Example:
................................................................
$PATH=:/user0/rharding/bin:/bin:/usr/bin .
$ .
................................................................
This PATH variable indicates to start the search for the program
at the current working directory, then look in the directory
/user0/rharding/bin, then /bin, and finally /usr/bin.
If each user has a unique path specified, each user can execute a
different program by giving the same command. The search for the
program stops when it is satisfied; thus, you can use the same
name for your own programs as the standard UNIX utilities. To do
this, simply put your program in one of the first directories
that the BourneShell searches.
1.7 INGRES Environment Variables
There are some environment variables that need to be in the
profile that set up INGRES. The following examples are given as
general guidelines, not actual entries to be made in your
profile.
1.8 ING_HOME
This is the INGRES home directory. This variable is valid for
version 5 of INGRES. This variable is set up in the following
manner.
Example:
................................................................
$ING_HOME=/user5/ingres .
................................................................
Notice that this environment variable is all capital letters.
This is a requirement in UNIX.
1.9 TERM_INGRES
If this variable is not set, INGRES will use the default terminal
type defined by the TERM variable in UNIX. It is not required
but difficulty in using the main INGRES menu can be experienced
if it is not used.
Example:
................................................................
$TERM_INGRES=vt100f .
................................................................
1.10 ING_EDIT
This variable defines the editor to use any time a user enters a
command that requires the use of an editor. The default is to
use the 'ed' editor.
Example:
................................................................
$ING_EDIT=/usr/bin/vi .
................................................................
Workshop 1
This workshop will reinforce your understanding of the material
presented in this chapter. Login using the username and the
password given to you by the instructor. Each student is to
complete the entire workshop.
DESK EXERCISES
1. What is the name of the file that is executed from your
home directory every time you log in?
2. What does the Shell variable HOME represent?
3. What does the Shell variable PATH represent?
4. What is a UNIX process?
5. When a command is given to the Shell it will fork a child
process to execute the command.
True/False
6. What is a process identification number (PID)?
Continue on the next page
7. What is the purpose of the trap command?
COMPUTER EXERCISES
8. Logon
9. What is the PID of your process?
10. Edit the .profile to include your home directory in the
path.
11. Modify the .profile so every time you login a listing of
the files in your current working directory (HOME) is
displayed.
12. Send a long listing of all the files in the current
working directory to the default printer and do it it
the background.
13. Logoff
NOTES
UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU
2. COMPILING "C" PROGRAMS
This chapter will examine compiling source code programs in three
high level languages "C", FORTRAN, and COBOL. The second part of
the chapter will look at the archive and library maintainer. The
archive allows you to create a library of object modules. These
files are used by the link editor.
2.1 "C": Sample Program with a Main and Two Functions in One
File
Based on the command line options, cc compiles, assembles, and
loads C language source code programs. It can also assemble and
load assembly language source programs or merely load object
programs.
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: cc [options] file-list ?
? ?
? (See Appendix E for a complete list of options) ?
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When using the cc utility, the following conventions are
observed:
1. A filename with the extension of .c indicates a C
language source program.
2. A filename with an extension of .s indicates an
assembly language source program.
3. A filename with an extension of .o indicates an object
program.
The cc utility will take its input from the file or files you
specify on the command line. Unless you use the -o option, it
will store the executable program in a file called a.out.
Sample C Language Source Code Program:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $cat hello.c 3
3 main () 3
3 { 3
3 printf ("Hello from main!\n\n"); 3
3 printf ("Calling function1!\n\n"); 3
3 funct1(); 3
3 printf ("\t Back from function1!\n\n"); 3
3 printf ("Calling function2!\n\n"); 3
3 funct2(); 3
3 printf ("\t Back from funct2!\n\n"); 3
3 printf ("That's all!\n\n"); 3
3 } 3
3 funct1() 3
3 { 3
3 printf ("\t\t Hello from function1!\n\n); 3
3 } 3
3 funct2() 3
3 { 3
3 printf ("\t\t Hello from function2!\n\n); 3
3 } 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
2.2 "C": Compiling a Program
To compile the previous example program into an executable
module, enter the following command at the command line.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $cc hello.c 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
Without any options, cc accepts C source code and assembly
language programs that follow the conventions outlined above. It
will compile, assemble, and load these programs to produce an
executable called a.out. The cc utility puts the object code in
files with the same base filename (everything before the period)
as the source but with a filename extension of .o. The a.out
stands for assembly output. This is the default.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $cc hello.c 3
3 $a.out 3
3 Hello from main! 3
3 3
3 Calling function1! 3
3 3
3 Hello from function1! 3
3 3
3 Back from function1! 3
3 3
3 Calling function2! 3
3 3
3 Hello from function2! 3
3 3
3 Back from function2! 3
3 3
3 That's all! 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
NOTE: The a.out file that was created by the cc utility has
the following permissions:
user - read, write, and execute
group - read and execute
other - read and execute
It is not necessary for you to change the permissions using the
chmod command because the cc utility set the execute permissions
for you.
2.3 "C": Renaming the Executable Module
You can rename the executable module using the mv command. The
file permissions will be the same as before the file is renamed.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $mv a.out hello 3
3 $hello 3
3 Hello from main! 3
3 3
3 Calling function1! 3
3 3
3 Hello from function1! 3
3 3
3 Back from function1! 3
3 3
3 Calling function2! 3
3 3
3 Hello from function2! 3
3 3
3 Back from function2! 3
3 3
3 That's all! 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
2.4 "C": Giving a Name to the Output File
It is possible to have the output sent to a file you specify
instead of a.out by using the following command.
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: cc -o output source ?
? ?
? output - the name of the executable file ?
? ?
? source - the name of the C source code file ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The -o option tells cc to tell the link editor to use the
specified name for the output instead of the default a.out.
NOTE: It is not necessary for the -o option to appear after
the cc command. The filename that appears after the -o
is the name of the output file. For example, cc source
-o output is the same as cc -o output source.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $cc -o hello.c 3
3 $hello 3
3 Hello from main! 3
3 Calling function1! 3
3 3
3 Hello from function1! 3
3 3
3 Back from function1! 3
3 3
3 Calling function2! 3
3 3
3 Hello from function2! 3
3 3
3 Back from function2! 3
3 3
3 That's all! 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
2.5 "C": Producing an Assembly Listing
This option causes cc to compile C programs and leave the
corresponding assembly language source programs in a file with
filename extensions of .s.
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: cc -S hello.c ?
? ?
? -S = Compile only ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $cc -S hello.c 3
3 $ls -C 3
3 example.f hello hex.c octal.c 3
3 hello.c hello.s multiply.c 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
2.6 "C": Main and Two Functions in Three Separate Source Files
This is the same C program that we have seen before, except it is
now in three files rather than one as before. The three files
are main.c, funct1.c, and funct2.c.
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $cat main.c 3
3 main () 3
3 { 3
3 printf ("Hello from main!\n\n"); 3
3 printf ("Calling function1!\n\n"); 3
3 funct1(); 3
3 printf ("\t Back from function1!\n\n"); 3
3 printf ("Calling function2!\n\n"); 3
3 funct2(); 3
3 printf ("\t Back from funct2!\n\n"); 3
3 printf ("That's all!\n\n"); 3
3 } 3
3 $cat funct1.c 3
3 funct1() 3
3 { 3
3 printf ("\t\t Hello from function1!\n\n); 3
3 } 3
3 $cat funct2.c 3
3 funct2() 3
3 { 3
3 printf ("\t\t Hello from function2!\n\n); 3
3 } 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
2.7 "C": Compiling but Not Producing an Executable Module
Using the previous program, the following command will compile
but not produce an executable module.
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: cc -c main.c funct1.c funct2.c ?
? ?
? -c = Compile, but do not load object files. This option ?
? causes cc to compile and/or assemble source code ?
? programs and leave the corresponding object programs ?
? in files with filename extensions of .o. ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $cc -c main.c funct1.c funct2.c 3
3 main.c: 3
3 funct1.c: 3
3 funct2.c: 3
3 $ls a.out 3
3 a.out not found 3
3 $ls -C *.o 3
3 funct1.o funct2.o main.o 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
The -c options causes the compilation system to suppress the link
edit phase. This produces an object file or files, in this
example (main.o funct1.o funct2.o), that can be link edited at a
later time with the cc command with no options.
3. COMPILING FORTRAN PROGRAMS
3.1 FORTRAN: Sample Program a Main and Two Subroutines
There are several conventions for use with the FORTRAN compiler.
They are:
1. The name of the file containing the FORTRAN source code
must end with .f.
2. The compiler is invoked with f77.
3. Several options are available with the compiler.
(-c, -o, -p, -S)
4. Preconnections are made for stdin (unit5) and stdout
(unit6).
This is the FORTRAN source code example to be used in the
following discussions of the FORTRAN compiler.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $cat hello.f 3
3 program calling 3
3 write(6,100) 3
3 100 format (' Hello from main!',/) 3
3 write(6,110) 3
3 110 format(' Calling subroutine1!',/) 3
3 call sub1 3
3 write(6,120) 3
3 120 format(t15' Back from subroutine1!',/) 3
3 write(6,130) 3
3 130 format(' Calling subroutine2!',/) 3
3 call sub2 3
3 write(6,140) 3
3 140 format(t15' Back from subroutine2!',/) 3
3 write(6,150) 3
3 150 format(' That's all, folks!') 3
3 end 3
3 subroutine sub1 3
3 write(6,200) 3
3 200 format(t20,' Hello from subroutine1!',/) 3
3 end 3
3 subroutine sub2 3
3 write(6,210) 3
3 210 format(t20,' Hello from subroutine2!',/) 3
3 end 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
3.2 FORTRAN: Compiling a Program
The FORTRAN compiler is invoked with the following command:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: f77 ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
To compile the above program into an executable program, use the
following command at the command line.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $f77 hello.f 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
Without any options, f77 accepts FORTRAN source code and assembly
language programs that follow the conventions outlined above. It
will compile, assemble, and load these programs to produce an
executable called a.out. The f77 utility outputs the object code
into files with the same base filename (everything before the
period) as the source but with a filename extension of .o.
The a.out stands for assembly output. This is the default.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $f77 hello.f 3
3 $a.out 3
3 Hello from main! 3
3 3
3 Calling function1! 3
3 3
3 Hello from function1! 3
3 3
3 Back from function1! 3
3 3
3 Calling function2! 3
3 3
3 Hello from function2! 3
3 3
3 Back from function2! 3
3 3
3 That's all! 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
NOTE: The a.out file that was created by the f77 utility has
the following permissions:
user - read, write, and execute
group - read and execute
other - read and execute
It is not necessary for you to change the permissions using the
chmod command because the f77 utility set the execute permissions
for you.
3.3 FORTRAN: Renaming the Executable Module
You can rename the executable module using the mv command. The
file permissions will be the same as before the file is renamed.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $mv a.out hello 3
3 $hello 3
3 Hello from main! 3
3 3
3 Calling function1! 3
3 3
3 Hello from function1! 3
3 3
3 Back from function1! 3
3 3
3 Calling function2! 3
3 3
3 Hello from function2! 3
3 3
3 Back from function2! 3
3 3
3 That's all! 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
3.4 FORTRAN: Giving a Name to the Output File
It is possible to have the output sent to a file you specify
instead of the default, a.out, by using the following command.
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: f77 -o output source ?
? ?
? output - the name of the executable file ?
? ?
? source - the name of the Fortran source code file ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The -o option tells the f77 utility to tell the link editor to
use the specified name for the output instead of the default
a.out.
NOTE: It is not necessary for the -o option to appear after
the f77 command. The filename that appears after the -
o is the name of the output file. For example, f77
source -o output is the same as f77 -o output source.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $f77 -o hello.f 3
3 $hello 3
3 Hello from main! 3
3 Calling function1! 3
3 3
3 Hello from function1! 3
3 3
3 Back from function1! 3
3 3
3 Calling function2! 3
3 3
3 Hello from function2! 3
3 3
3 Back from function2! 3
3 3
3 That's all! 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
3.5 FORTRAN: Producing an Assembly Listing
This option causes f77 to compile Fortran programs and leave the
corresponding assembly language source programs in a file with
filename extensions of .s.
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: f77 -S hello.f ?
? ?
? -S = Compile only ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $f77 -S hello.f 3
3 $ls -C 3
3 example.f hello hex.c octal.c 3
3 hello.c hello.s multiply.c 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
The file hello.s contains the assembly listing.
3.6 FORTRAN: Main and Two Subroutines in Three Separate Source
Files
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $cat main.f 3
3 program calling 3
3 write(6,100) 3
3 100 format (' Hello from main!',/) 3
3 write(6,110) 3
3 110 format(' Calling subroutine1!',/) 3
3 call sub1 3
3 write(6,120) 3
3 120 format(t15' Back from subroutine1!',/) 3
3 write(6,130) 3
3 130 format(' Calling subroutine2!',/) 3
3 call sub2 3
3 write(6,140) 3
3 140 format(t15' Back from subroutine2!',/) 3
3 write(6,150) 3
3 150 format(' That's all, folks!') 3
3 end 3
3 $cat sub1.f 3
3 subroutine sub1 3
3 write(6,200) 3
3 200 format(t20,' Hello from subroutine1!',/) 3
3 end 3
3 $cat sub2.f 3
3 subroutine sub2 3
3 write(6,210) 3
3 210 format(t20,' Hello from subroutine2!',/) 3
3 end 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
3.7 FORTRAN: Compiling But Not Producing an Executable Module
Using the above program, the following command will compile but
not produce an executable module.
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: f77 -c main.f sub1.f sub2.f ?
? ?
? -c = Compile, but do not load object files. This option ?
? causes f77 to compile and/or assemble source code ?
? programs and leave the corresponding object programs ?
? in files with filename extensions of .o. ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $f77 -c main.f sub1.f sub2.f 3
3 main.f: 3
3 MAIN: calling: 3
3 sub1.f: 3
3 sub1: 3
3 sub2.f: 3
3 sub2: 3
3 $ls a.out *.o 3
3 a.out not found 3
3 funct1.o 3
3 funct2.o 3
3 hello.o 3
3 main.o 3
3 sub1.o 3
3 sub2.o 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
The -c options causes the compilation system to suppress the link
edit phase. This produces an object file or files, in this
example (main.o sub1.o sub2.o), that can be link edited at a
later time with the f77 command with no options.
3.8 FORTRAN: Compiling Object Files to Produce an Executable
Module
The command to produce an executable nodule from several object
files is done in the following manner:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: f77 obj_1 obj_2 obj_3 ?
? ?
? obj_1 through obj_n - the object files ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $f77 main.o sub1.o sub2.o 3
3 $ls -C 3
3 funct1.o funct2.o hello.o main.o sub1.o sub2.o a.out 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
4. COMPILING COBOL PROGRAMS
4.1 COBOL: Sample Program with a Main and Two Subroutines
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $cat teacher.cob 3
3 identification division. 3
3 program-id. teacher. 3
3 environment division. 3
3 configuration section. 3
3 data division. 3
3 working-storage section. 3
3 procedure division. 3
3 begin section. 3
3 begin-it. 3
3 display " Hello from main!". 3
3 display " Calling subroutine1!". 3
3 perform subroutine1. 3
3 display " Back from subroutine1!". 3
3 display " Calling subroutine2!". 3
3 perform subroutine2. 3
3 display " Back from subroutine2!". 3
3 display " That's all, folks!". 3
3 stop run. 3
3 subroutine1 section. 3
3 sub1. 3
3 display " Hello from subroutine1!". 3
3 subroutine2 section. 3
3 sub2. 3
3 display " Hello from subroutine2!". 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
4.2 COBOL: Compiling a Program
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: cobol source_filename ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
Three files are created by the compiler. They are identified by
the same filename as the source code but with a different
extension. They have the extensions .IDY, .INT, and .LST.
NOTE: These extensions are uppercase characters. UNIX is
case sensitive.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $cobol teacher.cob 3
3 $ls teacher* 3
3 teacher.IDY 3
3 teacher.INT 3
3 teacher.LST 3
3 teacher.cob 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
4.3 COBOL: Running a Program
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $cbrun teacher.INT 3
3 Hello from Main! 3
3 Calling subroutine1! 3
3 Hello from subroutine1! 3
3 Back from subroutine1! 3
3 Calling subroutine2! 3
3 Hello from subroutine2! 3
3 Back from subroutine2! 3
3 That's all, folks! 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
NOTES
UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU
Workshop 2 through 4
This workshop will reinforce your understanding of the ideas
presented in this chapter. Login using the username and password
given to you by the instructor. Each student is to complete the
entire workshop.
DESK EXERCISES
1. "C": What is the command to compile, assemble, and load
source code programs?
2. "C": What is the filename extension that indicates a
source code program? An assembly language program? An
object code file?
3. "C": What is the default filename assigned to the
executable file?
4. "C": What command can be used to rename the executable
file produced by the cc compiler? What are the file
protections associated with the executable?
5. "C": What option will produce an assembly listing? What
is the filename extension of this file?
Continue on the next page
6. "C": What command will compile the source code program
but will not load object files but will keep the object
files in files with extensions of .o?
7. FORTRAN: What is the command to invoke the compiler?
8. FORTRAN: What is the filename extension for source code
programs?
9. FORTRAN: What is the name of the default
executable file?
10. FORTRAN: How can you change the permissions on the
executable module so anyone can execute it?
11. FORTRAN: What option on the call to the compiler will
allow you to specify the name of the executable file?
Continue on the next page
12. FORTRAN: What option on the call to the compiler will
produce an assembly listing? What is the filename
extension of this file?
13. FORTRAN: What option will produce object modules but
not produce an executable module?
14. FORTRAN: What command will produce an executable module
from several object modules?
15. COBOL: What is the command to call the compiler?
16. COBOL: What are the three files created by the
compiler? What are the filename extensions?
17. COBOL: Which of the three files that have been created
are used to run the program?
Continue on the next page
COMPUTER EXERCISES
18. Copy the following files from the directory
teacher:
main.c funct1.c funct2.c
Are these programs "C", FORTRAN, or COBOL? Compile these
three files creating an executable file called main1.exe and
then execute it. What are the file protections? Why?
19. Now append the three files into one file.
Use output redirection.
Compile the file creating the executable file called
main2.exe. Execute main2.exe.
20. Copy the following files from teacher into your
home directory:
main.f sub1.f sub2.f
Compile these three files creating an executable file
called main1.exe. Execute main1.exe
21. Now append the three files into one file.
Compile the file creating the executable file called
main2.exe. Execute main2.exe.
22. COBOL: Copy teacher.cob from teacher.
Compile and run.
5. THE make UTILITY
The make utility is used to keep a set of executable programs
current. This is based on the modification times of the programs
and the source code that each program is dependent upon. The
utility will look at the dependency lines in a file called
makefile in the current working directory. These dependency
lines indicate relationships between files, specifying a target
file that is dependent on one or more prerequisite files. If you
modified any of the prerequisite files more recently than the
target file, make will update the target file based on
construction commands that follow the dependency lines.
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: make [options] [target_files] ?
? ?
? See the online man pages for a detailed list of options ?
? ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The target_files refer to targets on dependency lines in the file
called makefile. If you do not specify a target_file, make will
update the first dependency line it finds in makefile.
The makefile has the following construction:
target: prerequisite_list
tab construction_commands
The dependency line is composed of target and the
prerequisite_list, separated by a colon. The
construction_commands must start with a tab character and must
follow the dependency line.
The target is the name of the file that is dependent on the files
in the prerequisite_list. The construction_commands are shell
commands that construct the target, these are usually compile
commands.
The make utility will execute the construction_commands when the
modification time of one or more of the files in the
prerequisite_list is more recent than the target.
Sample makefile:
payroll: sales.c salary.c
cc sales.c salary.c -o payroll
In the example, the target is called payroll. It is dependent on
sales.c and salary.c. If the modification time of either of
these is more recent than payroll, the construction_commands will
be executed. In this case, the source code programs are compiled
and stored in payroll.
In the previous example, to get the update to occur simply type
make.
Example:
................................................................
$make .
................................................................
Since no target was specified, the first dependency line is the
one that make will attempt to execute.
Each of the prerequisites on one dependency line can be a target
on other dependency lines. This nesting of specifications can
continue, creating a complex hierarchy that can specify a large
system of programs.
Sample makefile:
form: size.o length.o
cc size.o length.o -o form
size.o: size.c form.h
cc -c size.c
length.o: length.c form.h
cc -c length.c
form.h: num.h table.h
cat num.h table.h > form.h
Notice that form is dependent on two object files, size.o and
length.o. These two object files are, in turn, dependent upon
their respective source code programs and the header file,
form.h. The header file is dependent upon two other header
files. Note that the construction_commands for form.h can use
any shell command, in this case cat creates the header file.
This makefile can be quite difficult to write, especially if
there are a number of interdependencies. The make utility can
rely upon implied dependencies and construction_commands to make
your job of writing the makefile easier. If you do not include a
dependency line for a file, make assumes that object program
files are dependent on compiler or assembler source code files.
If a prerequisite for a target file is <filename>.o and
<filename>.o is not a target with its own prerequisites, make
will search for one of the following files in the current working
directory.
Filename Type of file
<filename>.c C source code
<filename>.f FORTRAN source code
<filename>.s Assembler source code
If you do not include a construction_command for one of the files
listed, make will create a default construction_command line that
will call the appropriate compiler or assembler to create the
object file.
grep: A PATTERN MATCHING FILTER
The grep utility can search through a file to see if it contains
a specified string of characters. The utility will not change
the file it searches but displays each line that contains the
string. The format for the string is as follows.
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: grep [options] limited_regular-expression [file] ?
? ?
? Use the man command for a complete list of options ?
? ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The grep utility searches files for a pattern and displays all
lines that contain the pattern. It uses limited-regular-
expressions (these are expressions that have string values that
use a subset of all the possible alphanumeric and special
characters) like those used with ed to match the patterns.
Be careful using the characters $, *, [, ^, |, (, ), and \ in the
regular expression because they will be evaluated by the Shell.
It is good practice to enclose the regular expression in single
quotes. This will prevent the Shell from evaluating these
special characters.
The grep utility will assume standard input if no files are
given. Normally, each line found in the file will be displayed
to standard output.
Sample session:
................................................................
$grep 'disc' memo .
................................................................
This command will search the file "memo" for the string "disc".
It will include words like discover and indiscreet because they
contain the characters "disc". The single quote marks are not
necessary, and for this example, they wouldn't have made any
difference. They do allow you to include spaces in the search
pattern.
5.0.1 More on Regular Expressions
The grep command can be best understood by a discussion of
regular expressions. Let's create a database of phone numbers
called phone.lis and then use regular expressions to search
through the database. Here is as listing of the contents of
phone.lis
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $cat phone.lis 3
3 Smith, Joan 7-7989 3
3 Adams, Fran 2-3876 3
3 StClair, Fred 4-6122 3
3 Jones, Ted 1-3745 3
3 Stair, Rich 5-5972 3
3 Benson, Sam 4-5587 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
The format for the records in this database is:
Last name, First name <tab> #-####
Using the database (phone.lis) above. What grep command would we
use to search through the database and get all the records that
had a person whose name contains an "S".
An alphabetic character represents itself.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $grep S phone.lis 3
3 Smith, Joan 7-7989 3
3 StClair, Fred 4-6122 3
3 Stair, Rich 5-5972 3
3 Benson, Sam 4-5587 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
This grep command searched for the string "S" and then listed all
the lines in phone.lis that matched.
A single . (dot) is used to represent any single character.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $grep .S phone.lis 3
3 Benson, Sam 4-5587 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
A $ represents the end of the line.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $grep 5$ phone.lis 3
3 Jones, Ted 1-3745 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
A ^ represents the beginning of the line
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $grep ^S phone.lis 3
3 Smith, Joan 7-7989 3
3 StClair, Fred 4-6122 3
3 Stair, Rich 5-5972 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
Regular expressions must get to grep in order for them to be
evaluated properly. Let's say we want to get the records of
employees that have a phone number that begins with a "4".
What does the following expression do?
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $grep <tab>4 phone.lis 3
3 StClair, Fred 4-6122 3
3 Jones, Ted 1-3745 3
3 Benson, Sam 4-5587 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
Why did we get the record of Ted Jones? The tab character was
evaluated by the Shell and so the search was actually made
looking for a "4". This is the same as if we had entered $grep 4
phone.lis.
We must prevent the Shell from evaluating these characters, this
is done with the \ (backslash) character as shown in the next
example.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $grep \<tab>4 phone.lis 3
3 StClair, Fred 4-6122 3
3 Benson, Sam 4-5587 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
Now it worked properly. It searched for a <tab> character
followed by the number 4. The [] (left and right brackets) are
used to identify a range of characters.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $grep \[AF] phone.lis 3
3 Adams, Fran 2-3876 3
3 StClair, Fred 4-6122 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
Why do [] need to be quoted? In the previous example the search
makes a match on "A" or "F".
A - (dash) can indicate inclusion. For example, we want to make
a match on a phone number that has a 1, 2, 3, or 4. How can this
be done? Here's an example:
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $grep \[1-4] phone.lis 3
3 Adams, Fran 2-3876 3
3 StClair, Fred 4-6122 3
3 Jones, Ted 1-3745 3
3 Stair, Rich 5-5972 3
3 Benson, Sam 4-5587 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
A ^ character looks for all characters NOT inside the []
brackets.
For example,
[^0-9] matches all non-digits
[^a-zA-Z] matches all non-alphabetic characters
NOTE: \, *, and $ lose their metacharacter meanings
inside the []. Also the ^ character is special
only if it appears first.
What is the following command searching for?
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $grep '[^789]$' phone.lis 3
3 Adams, Fran 2-3876 3
3 StClair, Fred 4-6122 3
3 Jones, Ted 1-3745 3
3 Stair, Rich 5-5972 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
5.0.2 Still More Regular Expressions
The * (asterisk) represents zero or more of the characters
preceding the asterisk.
A* represents 0 or more As.
AA* represents 1 or more As.
[0-9]*$ 0 or more digits at the end of a line
(last four digits in a phone number)
.* represents 0 or more of any character.
How would you write a grep command using regular expressions to
find the last name starting with an "S" and the first name with
an "F"?
^S Begins with an "S"
.*,F Any number of characters before ,F
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $grep ^S.\*,F phone.lis 3
3 StClair, Fred 4-6122 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
NOTE: The * (asterisk) was quoted so the Shell didn't try to
evaluate it.
It is very desirable to quote the entire string to keep the Shell
from doing an expansion or substitution. It also increases
readability of the regular expression as in the following
example.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $grep '^S.*, F' phone.lis 3
3 StClair, Fred 4-6122 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
5.0.3 Some Nice grep Options
The grep provides several options that modify how the search is
performed.
-c Report count of matching lines only
-v Print those lines that don't match the pattern.
What will these lines print?
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $grep -c '[J-Z]' phone.lis 3
3 5 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
Why did we get this result? Let's analyze the command. In
English, this command could be interpreted to mean "Tell me how
many records in the file "phone.lis" contain a letter from the
set J through and including Z." Look at the phone.lis file and
see that five records fit this restriction. So the answer is 5.
Now look at another example and see what this one does.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $grep -v '[J-Z]' phone.lis 3
3 Adams,Fran 2-3876 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
Why is this the only record that was found? The -v option says
to select records that don't match the pattern. This is the same
pattern as the previous example and therefore it selects records
that don't match the pattern. The "Adams" record is the only one
that doesn't make a match. It doesn't have a character from the
set J through and Z.
5.0.4 Summary of Regular Expression Characters
^ Beginning of the line
$ End of the line
* 0 or more preceding characters
. Any single character
[...] A range of characters
[^...] Exclusion range of characters
sed: EDIT A FILE TO STANDARD OUTPUT
UNIX provides a method of editing streams of data. It is the sed
utility. The name of this utility is derived from Stream EDitor.
This is not the same as the vi editor. The vi editor edits text
in a file. The sed utility edits text in a stream. In order to
edit a character stream two things are required. First, the line
to edit must be identified (regular expressions) and second, how
to edit the line.
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: sed [-n] [-e script] [-f sfile] [files] ?
? ?
? Details in on-line man pages ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The sed utility copies the named files (standard input default)
to the standard output, edited according to a set (script) of
commands. The -f options cause the script to be taken from file
"sfile".
The general form is:
$sed /address/instruction
NOTE: If no address is specified, all lines are chosen to
edit.
'sed' addresses can be line numbers or regular expressions.
Example:
line numbers 2,4
2,$ ($ represents the last line)
textual address /regular-expression/
NOTE: Forward slashes enclose textual addresses
The sed instructions indicate what editing function to perform.
Here some useful sed instructions:
s substitute
d delete
NOTE: Most sed command lines contain spaces or metacharacters
and they should be quoted to protect them from the
Shell. There are many more editing commands provided
by sed. The following is a sample sed command to edit
the records in the database file that we are already
familiar with; namely, phone.lis.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $sed /s/Smith/Smythe/ phone.lis 3
3 Smythe, Joan 7-7989 3
3 Adams, Fran 2-3876 3
3 StClair, Fred 4-6122 3
3 Jones, Ted 1-3745 3
3 Stair, Rich 5-5972 3
3 Benson, Sam 4-5587 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
sed is an editor. It simply copies the standard input to the
standard output, editing the lines that match the indicated
address. The original file is not changed.
Here's another example of a sed command.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $sed '2,4 s/2$/3/' phone.lis 3
3 Smith, Joan 7-7989 3
3 Adams, Fran 2-3876 3
3 StClair, Fred 4-6123 3
3 Jones, Ted 1-3745 3
3 Stair, Rich 5-5972 3
3 Benson, Sam 4-5587 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
What does this sed command do? If you read command in English it
reads like this: On lines 2 through 4 substitute the 2 at the end
of the line with a 3. Notice that the phone number for
StClair, Fred changed from 4-6122 to 4-6123. The number for
Stair, Rich didn't change because it was outside the range.
The sed utility can also be use to delete parts of a line of
data. This is done by substituting nothing for the parts you
want to delete. It looks like this:
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $sed 's/^.*, //' phone.lis 3
3 Joan 7-7989 3
3 Fran 2-3876 3
3 Fred 4-6122 3
3 Ted 1-3745 3
3 Rich 5-5972 3
3 Sam 4-5587 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
Reading this command it means:
Substitute from the beginning of the line followed by any number
of characters followed by a comma with the null string (nothing).
This has the effect of removing the text.
Here's a delete command and how it's used.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $sed d phone.lis 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
Why is there no output? Well, it read standard input and did the
editing function on all the selected lines. Since no lines were
specified all lines were selected to be edited. The editing was
to delete the line.
Question: Has the original file been destroyed?
Multiple commands are allowed in sed. Each instruction is
applied to each input line.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $sed '/Stair/d 3
3 >/Adams/d' phone.lis 3
3 Smith, Joan 7-7989 3
3 StClair, Fred 4-6122 3
3 Jones, Ted 2-1136 3
3 Benson, Sam 4-5587 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
The records for Adams and Stair have both been removed from the
database.
NOTE: The > character is the BourneShell secondary prompt.
awk: A PATTERN MATCHING PROGRAMMING LANGUAGE
Suppose you wanted to change the format of the database phone.lis
to be the first name followed by the last name. There is no easy
way to do this with sed. Fortunately, UNIX not only provides a
stream editor (sed) but it also has a formatting tool. The
formatting tool in UNIX is called awk. This tool is named after
authors who wrote it Alfred V. Aho, Peter J. Weinberger, and
Brian W. Kerninghan so it really doesn't have any meaning.
The awk utility is a pattern scanning and processing language.
It will search one or more files for a specified pattern and then
performs an action, such as writing to standard output or
incrementing a counter when it finds a match. You can use awk to
generate reports or filter text. It works equally well with
numbers or text. The authors designed it to be easy to use and
sacrificed execution speed toward this end.
While the sed utility allows us to change the text in a stream,
awk allows us to easily rearrange, add, or delete text in a
stream.
The awk takes advantage of many constructs from the C programming
language. It has the following features:
flexible format
conditional execution
looping statements
numeric variables
string variables
regular expressions
C's printf
The awk will take its input from the files you specify on the
command line or from standard input. The following is the format
for awk:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command format: awk [-Fc] [prog] [files] ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The awk will scan each line of file for lines that match a set of
patterns specified by prog. With each pattern in prog there can
be an associated action to be performed when the line is found.
The set of patterns may appear literally as prog, or in a file
specified as -f file. The prog string should be enclosed in
single quotes to protect it from the Shell.
Files are read in order and if there are none specified the
standard input is read. Each line is matched against the pattern
portion of every pattern-action statement. The associated action
is performed for each matched pattern. An input line is made up
fields separated by white space. $1, $2.. define the fields. $0
refers to the whole line.
A pattern-action statement has the form:
pattern {action}
A missing action means print the line; a missing pattern always
makes a match. A statement can be one of the following:
if (conditional) statement [else statement]
while (conditional) statement
for (expression;conditional;expression) statement
break
continue
{[statement]...}
variable=expression
print [expression-list] [>expression]
printf format [,expression-list][>expression]
next # skip remaining pattern on this input line
exit # skip the rest of the input
Statements are terminated by semicolons, new lines (Ret), or
right braces.
Let's look at the syntax for awk in a little simpler manner.
awk 'commands' [filename]
An awk program (commands) consists of a optional pattern to match
and an action to perform if a match is found on the current line.
This syntax looks like this:
awk '/pattern/{action}' [filename]
The pattern used is a regular expression enclosed in forward
slashes. If no pattern is listed, the action will be performed
for every line. An action can contain several commands. There
can be multiple patterns and actions.
awk '/pattern1/{action1}
/pattern2/{action2}' [filename}
One of awk's commands is print. It puts the current line on
standard output.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $awk '{print}' phone.lis 3
3 Smith, Joan 7-7989 3
3 Adams, Fran 2-3876 3
3 StClair, Fred 4-6122 3
3 Jones, Ted 1-3745 3
3 Stair, Rich 5-5972 3
3 Benson, Sam 4-5587 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
The awk splits every input line at whitespace and keeps track of
the number of fields on each line and counts the number of lines
read. Each field is identified by its field number and a $.
$1 Identifies the first field
$2 Identifies the second field
.
$0 Identifies the entire line
NF Identifies the number of fields on the line
NR Identifies the number of lines that have been read
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $awk '{print NR,$1}' phone.lis 3
3 1 Smith, 3
3 2 Adams, 3
3 3 StClair, 3
3 4 Jones, 3
3 5 Stair, 3
3 6 Benson, 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
To change the order of the names in phone.lis, use awk. The
comma in the print command tells awk to separate each field with
a space. Without the comma, the output would have no spacing.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $awk '{print $2, $1 "<tab>"$3}' phone.lis 3
3 Joan Smith, 7-7989 3
3 Fran Adams, 2-3876 3
3 Fred StClair, 4-6122 3
3 Ted Jones, 1-3745 3
3 Rich Stair, 5-5972 3
3 Sam Benson, 4-5587 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
sort: SORT A FILE
The sort utility sorts line of all the named files together and
writes the result to standard output. The standard input is used
if - is used as a file name or no input files are specified.
Comparisons are based one or more sort keys extracted from each
line of input. There is only one key by default, that's the
entire line, and ordering is lexicographic by bytes in machine
collating sequence.
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command format: sort [-cmu][-ooutput][-ykmem][-zrecsz] ?
? [-dfiMnr][-btx][+pos][-pos2][files] ?
? ?
? See on-line manual for options etc. ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The easiest way to use sort is to add it at the end af a
pipeline. What does the following command line accomplish:
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $grep '<tab>[45]' phone.lis | sed 's/<tab>/<tab>73/' | sort 3
3 Benson, Sam 734-5587 3
3 StClair, Fred 734-6122 3
3 Stair, Rich 735-5972 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
The grep command will select only those records that have a 4 of
a 5 in the phone number, those records are then sent to sed which
will add "73" just after the tab character, then the records are
sent to sort and put in alphabetical order. Notice that there is
a problem here, should StClair come before Stair in an
alphabetical listing? The answer is NO. Why did this happen?
It occurred because of the collating sequence for the default
sort.
This can be fixed by specifying some options on the call to the
sort utility. Here are some options for sort. Let's see if we
can determine how to remedy the problem discovered in the default
sort.
sort options:
-f Fold lower case into upper case
-r Reverse the sort from highest to lowest
-b Ignore leading blank spaces
-d Dictionary sort - ignore nonalphanumeric characters
-m Merge two sorted files together
-n Sort the list as numbers not digit characters
Notice the -f options folds lower case into upper case. This
option will make the sort for our problem work correctly.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $grep '<tab>[45]' phone.lis|sed 's/<tab>/<tab>73/'|sort -f 3
3 Benson, Sam 734-5587 3
3 Stair, Rich 735-5972 3
3 StClair, Fred 734-6122 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
The sort can also be directed to use only a portion of the line
as a sorting key versus the entire line. The utility will
automatically break each line into fields at whitespace
delimiters. You can use a character other than whitespace by
using the -t option. The fields are set up like this:
0 1 2
/----|/---|/-------------|
Adams, Fran 2-3876
In order to sort by the second field, here is the sort command to
enter.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $sort +1 phone.lis 3
3 Adams, Fran 2-3876 3
3 StClair, Fred 4-6122 3
3 Smith, Joan 7-7989 3
3 Stair, Rich 5-5972 3
3 Benson, Sam 4-5587 3
3 Jones, Ted 1-3745 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
Here's a sample of a sort on the 3rd field.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $sort +2 phone.lis 3
3 Jones, Ted 1-3745 3
3 Adams, Fran 2-3876 3
3 Benson, Sam 4-5587 3
3 StClair, Fred 4-6122 3
3 Stair, Rich 5-5972 3
3 Smith, Joan 7-7989 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
A sort can also be performed by a character position within a
field.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $sort +2.4 phone.lis 3
3 StClair, Fred 4-6122 3
3 Benson, Sam 4-5587 3
3 Jones, Ted 1-3745 3
3 Adams, Fran 2-3876 3
3 Stair, Rich 5-5972 3
3 Smith, Joan 7-7989 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
NOTE: The first character of a field is the delimiter for
that field.
5.1 ARCHIVER AND LIBRARY MAINTAINER
This command will maintain groups of files combined into a single
archive file. The main use of ar is to create and update library
files as used by the link editor. It can also be used for any
other similar purpose. The file header consists of printable
ASCII characters. If the archive consists of printable
characters, then the entire archive is also printable.
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: ar key [posname] afile [name]... ?
? ?
? Unlike command options, the command key is required. The key,?
? usually a - sign, is formed with one of the following letters ?
? drqtpmx. Arguments to the key are made from one or more of ?
? the following set, vuaibcis. See Appendix I for a complete ?
? list of command keys. ?
? ?
? posname is an archive member name used as a reference for ?
? positioning other files in the archive. ?
? ?
? afile is the name of the archive. ?
? ?
? name[s] are the constituent files in the archive. ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
To illustrate how to create and use an archive file, we will use
the "C" program called main.c and the two functions, funct1.c and
funct2.c. First, create the object files that we intend to put
into the archive file.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $cc -c main.c funct1.c funct2.c 3
3 main.c: 3
3 funct1.c: 3
3 funct2.c: 3
3 $ls -C *.o 3
3 funct1.o funct2.o main.o 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
Remember the -c option will not produce an executable module, but
it does create the object modules. These object modules are file
files that we will place into an archive.
5.2 Creating an Archive File with Object Modules
In this call to ar, we will use the r command key which will
replace the named files in the archive. The v option will give a
verbose file-by-file description of the making of the new archive
file.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $ar rv functs.a funct1.o funct2.o 3
3 a - funct1.o 3
3 a - funct2.o 3
3 ar: creating functs.a 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
The name of the new archive file is functs.a. The files that
have been added to that archive are funct1.o and funct2.o. The
file protections for the new archive file are rw-r--r--.
5.3 Verifying the Contents of the Archive File
The key command to list the table of contents is t. The t
command will print a table of contents of the archive file. When
the v option is used with the t command it will give a long
listing of all information about the files.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $ar tv functs.a 3
3 rw-r--r-- 115/ 200 448 Sep 27 09:56 1990 funct1.o 3
3 rw-r--r-- 115/ 200 448 Sep 27 09:56 1990 funct2.o 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
This output shows that there are two members in this archive
file, namely, funct1.o and funct2.o.
The protections of these files is:
owner - read and write
group - read
other - read
The fields are, left to right, the file protections, owner,
group, size (in bytes), creation date and time, and finally the
name of the constituent.
5.4 Removing Duplicate Object Files
Once the archive has been created and verified, the object files
in your directory can be deleted. This can be accomplished with
the rm command.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $rm funct?.o 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
The question mark (?) is a wildcard that stands for any single
character. The files funct1.o and funct2.o no longer exist in
your subdirectory.
5.5 Compiling Main and Archive Files
Now that the object files, funct1.o and funct2.o, are in the
archive file functs.a you, can link them with main.o in the
following manner.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $cc -o new_hello main.o functs.a 3
3 $ls -la new_hello 3
3 -rwxr-xr-x 1 teacher class 17570 Sep 27 12:58 new_hello 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
Workshop 5
This workshop will reinforce your understanding of the ideas
presented in this chapter. Login using the username and password
given to you by the instructor. Each student is to complete the
entire workshop.
DESK EXERCISES
1. What does the UNIX utility grep do?
2. What do the following regular expressions represent?
^Ba
.*
BB*
J*
[0-9]*$
3. What does the UNIX utility sed do?
Continue on the next page
4. What does the UNIX utility awk do?
5. What does the UNIX utility sort do?
6. What is the main use for the UNIX utility ar?
Continue on the next page
COMPUTER EXERCISES
Use the phone.lis database file to answer the following
questions.
7. "I want to find all the phone numbers that begin with a
4 and end with a 2"
8. "I can't remember the name but I believe the last name
starts with an S and the first name with an F"
9. Find all the people with 3 character first names.
10. Write a grep command that finds all the phone numbers
that don't begin with a 4, 5, or 6.
11. Write a grep command that finds all entries beginning
with J-Z and ending with a 2 or 5.
12. Put a 23 in front of every phone number. (Hint: sed)
13. Replace the first name with the person's first initial
and a period.
Continue on the next page
14. Task: A new phone system has been installed and people
with phone extensions beginning with 4 or 5 now have a
new prefix: 73. Create a file of only the people with
the new phone numbers.
15. Print out the phone list showing last name and first
name in the following format and sorted by last name.
First name <tab> Last name
That's enough, don't you think?
6. UNIX UTILITIES PART I - DISPLAY AND MANIPULATE FILES
Problem: I want to know what the differences are between two
sorted files.
Solution: comm command
The formal form for the comm command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: comm [ - [ 123 ] ] file1 file2 ?
? ?
? Details in on-line man pages ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
This command will display a line-by-line comparison of two sorted
files. The output is divided into three columns. The first
column shows the lines only found in the first file, the second
shows the lines only found in the second file, and the third
column shows the lines common to both.
Sample session:
................................................................
$comm comm_file1 comm_file2 .
................................................................
Problem: I want to store and retrieve files in an archive format
to create backups, transport files to another
compatible system or create archives.
Solution: cpio command
The formal form for the cpio utility is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: cpio -o[options] ?
? ?
? cpio -i[options] [patterns] ?
? ?
? cpio -p[options] directory ?
? ?
? ?
? See on line man pages for details on options ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The cpio utility has three functions. It can copy one or more
files into a single archive file, retrieve files from a
previously created archive file, or it can copy directories. The
three major options are:
-o (out) This option will cause cpio to read standard
input to get pathnames of plain files. It
combines these along with header info into a
single archive file that it copies to
standard output.
-i (in) This option will read standard input (which
must have been created with the -o option).
It extracts files based on patterns you
provide as arguments.
-p (pass) This option causes cpio to read its standard
input to obtain a list of filenames. It
copies these files to a directory you
specify.
Problem: I have two files and I want to know the differences
between them.
Solution: diff command
The formal form for the diff command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: diff [options] file1 file2 ?
? ?
? See online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
This command will display the differences between two files on a
line-by-line basis. The differences are displayed as commands
you can use to make the two files equal.
Sample session:
................................................................
$diff diff_file1 diff_file2 .
................................................................
Problem: I can't remember the name of a file but I know it is in
a specific subdirectory and I do know some of its
attributes.
Solution: find command
The formal form for the find command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: find directory_list expression ?
? ?
? See online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The directory_list contains the pathnames of a directory or
directories that find will search. The expression contains one
or more search criteria. The utility will test each of the files
in the directory_list to see if meets the criteria described by
the expression.
Sample session:
................................................................
$find . -name 'm* ' -print .
................................................................
Problem: I want a file that exists in another users directory to
appear in my directory listing.
Solution: Create a link to that file using the ln command
The formal form for the ln command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: ln existing_file new_link ?
? ?
? ln existing_file_list directory ?
? ?
? See the online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The existing_file is the pathname to the file you want to make a
link to. The new_link is the pathname to the new link. The
second format allows existing_file_list entries which are
pathnames that you want links to, they will appear in directory.
Problem: I want to see contents of a file displayed in octal
format.
Solution: Use the od command to display the file in the selected
format.
The formal form for the od command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: od [options] filename ?
? ?
? See online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
This command is useful for viewing executable (object) files and
text files with embedded nonprinting characters. The dump can be
shown in octal (default) or hexadecimal or character or decimal.
The name od is short for octal dump.
Sample session:
................................................................
$od -c memo .
................................................................
Problem: I want to print and format the contents of a specific
file.
Solution: pr command.
The formal form for the pr command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: pr [options] file_list ?
? ?
? See the online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
This command will break up files into pages, usually before
printing. Each page will have a header with the name of the
file, date, time, and page number. Usually the output if pr is
piped to lp so the file can be printed.
Sample session:
................................................................
$pr memo | lp .
................................................................
Problem: I just wrote a memo and I want to check for mis-spelled
words.
Solution: spell command
The formal form for the spell command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: spell [options] file_list ?
? ?
? See online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The spell command will display all words that are not in the
dictionary or that can be derived from those words. You can
specify more than one file but only one list of misspelled words
will be shown.
Sample session:
................................................................
$spell memo .
................................................................
Problem: I want to write a file to tape and later retrieve it
back into my directory.
Solution: tar command
The formal form for the tar command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: tar key[options] [file_list] ?
? ?
? See online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
This command can create, add to, list, or retrieve files from an
archive file. The archive file is usually stored on tape. The
name tar is short for tape archive.
Problem: How many lines are in this file? How many words are in
this file? How many characters are in this file?
Solution: wc command
The formal form for the wc utility is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: wc [-lwc] filename ?
? ?
? See online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
Sample session:
................................................................
$wc memo .
................................................................
7. UNIX UTILITIES PART II - DISPLAY AND ALTER STATUS
Problem: I want to change the group for a particular file so
users outside my group can have access.
Solution: chgrp command
The formal form for the chgrp command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: chgrp group file_list ?
? ?
? See online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
Sample session:
................................................................
$chgrp class memo .
................................................................
Problem: I want to transfer ownership of a file to another user.
Solution: chown command
The formal form for the chown command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: chown owner file_list ?
? ?
? See the online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The chown command is short for change owner. Only the owner or
Superuser can change the ownership of a file.
Example:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $chown rharding /u/do/teacher/memo 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
The file /u/do/teacher/memo is now owned by the username
rharding.
Problem: How can I find out how much space I have left on my
disk partition?
Solution: df command
The formal form for the df command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: df [options] [file_system_list] ?
? ?
? See the online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The df (disk free) command will show how much free space is
remaining on any mounted device or directory. The amount of
space left is usually displayed in blocks. Each block is 1024
bytes in length.
Sample session:
................................................................
$df .
................................................................
Problem: How much space does this file occupy on the disk?
Solution: du command
The formal form for the du command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: du [options] [file_list] ?
? ?
? See the online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The du (disk usage) command reports how much space a directory
and all its subdirectories occupy. It tells the size in blocks,
usually 1024 bytes each.
Sample session:
................................................................
$du -s .
472 . .
$ .
................................................................
Problem: I started a process that I don't need anymore. How can
I get rid of it?
Solution: kill it with the kill command
The formal form for the kill command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: kill [option] PID_list ?
? ?
? See the online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The kill command can stop a process by sending a software
termination signal (number 15) to a process. The process being
killed must belong to the user of the kill command. The
Superuser can, however, kill any process. A message will be
displayed indicating that the process was killed.
Sample session:
................................................................
$compute & .
1742 .
$kill 1742 .
................................................................
Problem: There are some files I need access to but they are in
another group. How can I get access to them?
Solution: newgrp command
The formal form for the newgrp command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: newgrp [group] ?
? ?
? See online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
This command will fork a new Shell and while in that Shell you
have the privileges of the group you named on the command line.
In order for you to use this command you must be listed in the
/etc/group file as a member of the group. If you don't specify a
group it will change you back to the default as specified in the
/etc/passwd file.
Sample session:
................................................................
$newgrp pubs .
................................................................
Problem: This job can be run at a lower priority than default.
I want to be a good user and lower the priority so the
system can run more efficiently. Can I do that?
Solution: nice command
The formal form for the nice command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: nice [option] command_line ?
? ?
? See the online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
This command will execute the command line at a lower priority
than normal. You can specify a range from 1-19. Sorry, only the
Superuser can raise the priority.
Sample session:
................................................................
$nice -19 nroff -m chapter1 > chapter1.out & .
................................................................
Problem: I want the following command to run to completion even
after I logout of the system. Is that possible?
Solution: nohup command
The formal form for the nohup command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: nohup command_line ?
? ?
? See the online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
This command will allow the command that was started to continue
running even though you logout. Normally when you logout, all
processes that you started are killed by the system.
Sample session:
................................................................
$nohup nroff -m memo > memo.out & .
................................................................
Note that this process was started in the background.
Problem: What is the status of the process I just started?
Solution: ps command
The formal form for the ps command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: ps [options] ?
? ?
? See the online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
With no options specified, ps will display the status of all
active processes that your terminal controls.
Problem: I want to make my process inactive for a few minutes so
the user can read the screen before continuing.
Solution: sleep command
The formal form for the sleep command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: sleep time ?
? ?
? See the online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The sleep command will cause the process executing it to sleep
for the time you specify. The time is indicated in seconds. It
must be less than 65,536.
Problem: I have just logged into a different terminal than I
normally use. It doesn't act right. How can I change
the attributes for my new terminal?
Solution: stty command
The formal form for the stty command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: stty [arguments] ?
? ?
? See the online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
With no arguments, stty will report certain parameters affecting
the operation of your terminal. The mode of data transmission,
the treatment of characters, the data line specification, and
transmission delays can all be set to different values.
Problem: I don't like the default protections for files that I
create using the editor. How can I change the default
so my files can't be read by others outside my group?
Solution: umask command
The formal form for the umask command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: umask [mask] ?
? ?
? See the online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
This command will specify the mask that will be used by the
system to set the file protections when you create a file. Mask
is a three digit octal number. When you create a file the system
will subtract these numbers from the system defined protections
and the resultant protection will be assigned to the newly
created file.
8. UNIX UTILITIES PART III - MISCELLANEOUS
Problem: I just wrote a BourneShell script and I want it to
execute once a week at midnight. Can this be done in
UNIX?
Solution: at command
The formal form for the at command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: at time [date] [+ increment] ?
? ?
? at [options] job_list ?
? ?
? See the online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The at command causes the system to execute commands it gets from
standard input. It executes them as a Shell script in the
working directory at a time you specify.
Sample session:
................................................................
$at 2am .
pr long_file | lp .
Ctrl-d .
job 474285699.a at Fri Jan 11 02:00:00 1991 .
$ .
................................................................
Problem: I need to display a message on the screen?
Solution: echo command
The formal form for the echo command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: echo message ?
? ?
? See the online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
This command will copy its arguments, followed by a carriage
return, to standard output.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $echo "This is an example" 3
3 This is an example 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
Problem: I want to send some output to a file and I want to see
it displayed on my screen at the same time.
Solution: tee command
The formal form for the tee command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: tee [options] file_list ?
? ?
? See the online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The tee command copies standard input to its standard output and
to one or more files you specify.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $date | tee hold.date 3
3 Wed Dec 19 09:32:22 PST 1984 3
3 $cat hold.date 3
3 Wed Dec 19 09:32:22 PST 1984 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
Problem: What is my terminal pathname?
Solution: tty command
The formal form for the tty command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: tty ?
? ?
? See the online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The tty command displays the pathname of its standard input file
if it is a terminal.
Sample session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $tty 3
3 /dev/tty11 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
Problem: How can I update the modification date of a file
without loading it into the editor and really making a
change?
Solution: touch command
The formal form for the touch command is as follows:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: touch [options] file_list ?
? ?
? See the online man pages for details ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The touch command will read a byte from the file an write it back
so the update time associated with the file will be updated. If
the file doesn't exist it will create it unless you specify the
option not to create the file.
Workshop
This workshop will reinforce your understanding of the material
presented in this chapter. Login using the username and the
password given to you by the instructor. Each student is to
complete the entire workshop.
DESK EXERCISES
1. What UNIX command would you use to find out the
differences between two files?
2. How could you find a file in a subdirectory when you
don't know the name?
3. What command can link a file to another directory?
4. The od command stands for octal dump. Can you display the
contents in hexadecimal?
5. What is the command to change group?
6. Can I change the ownership of a file that I don't own?
What is the command to change the ownership of a file
that I do own?
Continue on the next page
7. What command would you use to kill a child process?
8. I want to be nice. What command can I use to lower the
priority of a process?
9. I want to start a process in the background and then
logoff. The child process will run to completion. How?
10. What is the at command?
Continue on the next page
COMPUTER EXERCISES
11. Use the appropriate command to determine if the file vi
is located in the /bin directory. If not, where is it?
12. Create a link to a file in another students directory.
13. Run the spell checker against the file called memo.
14. How many files are in the teacher subdirectory?
15. Change ownership of one of your files to another
student.
16. How much disk space is remaining on your directory?
Continue on the next page
17. Make a copy of the file called teacher/prob_17 to
your home directory. Execute it in background. Find
out its PID and then kill it.
18. Use the tee command and echo a message of your choice to
the file called message1 and your monitor screen.
19. Logout
9. ADVANCED FEATURES OF FTP
This chapter will discuss some advanced features of the FTP
server as implemented on the Multimax. The introduction of FTP
in UNIX for Beginning Users gave an elementary introduction to
some of the features. If you are not familiar with the basics,
please refer to that manual. It is not the purpose to review
those basics here.
The FTP (Internet file transfer program) is the user interface to
the DARPA File Transfer Protocol. This utility program will
transfer files to and from a remote computer. In order for files
to be transferred from the local computer to a remote computer, a
connection must be established. This can be done from the FTP
command line. The connection to the remote computer will remain
active until it is terminated by the user.
The remote computer with whom the connection is to be made can be
specified on the FTP command. In this case, FTP will immediately
try to establish a connection. If the remote computer is not
specified, FTP will enter its command interpreter mode and wait
for instructions; a prompt will be displayed.
FTP does have a help feature, and all 58 commands can be listed.
It will also give a terse description of each command. In
addition, there are on-line manual pages which can be accessed by
using the man command in UMAX.
9.1 Initializing FTP on UMAX
The term, "local computer," will refer to the Multimax. The
"remote computer" will refer to the other computer with which you
are trying to send/receive files. For purposes of this course,
we will be referring to the VAX minicomputer as the remote
computer. Please be aware that these procedures will work for
any computer connected to Ethernet and having an FTP server.
FTP can be invoked on the local computer using the following
syntax:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: ftp [-v] [-d] [-i] [-n] [-g] [host] ?
? ?
? -v = verbose on, forces ftp to show all responses ?
? from the remote server ?
? ?
? -d = enables debugging ?
? ?
? -i = turn off interactive prompting during ?
? multiple file transfers. ?
? ?
? -n = disables the "auto-login" feature ?
? ?
? -g = disable filename globbing ?
? ?
? host = the name of the remote computer ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
NOTE: UMAX (UNIX) is case sensitive. The commands and
options must be entered as shown.
9.2 Multiple File Transfers
The syntax for the multiple get command is:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: mget remote-files ?
? ?
? remote-files = remote computer wildcard specification ?
? or ?
? file1 file2 ... filen ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
The remote computer wildcard specification is expanded in a
process called globbing. Once the globbing is complete, a get is
performed on each filename; and it is transferred to the local
computer. The filename is the same on both computers. You can
specify the filenames to be transferred separating them with
spaces.
Example:
................................................................
ftp>mget *.dat;* .
................................................................
This command will transfer all versions of the remote-files that
have the filename extension of .dat. If the option -i was
specified on the call to FTP, then the files will be transferred
automatically. If the option was not specified, FTP will prompt
you before transferring each file.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 ftp>mget *.dat 3
3 mget change_pass.dat;1? 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
The default is 'yes', pressing (Ret) will cause the file to be
sent to the local directory. If you don't want this file
transferred, enter n(Ret); you will then be prompted for the next
file, if one exists.
9.3 Auto Login Feature
It is possible to have the login procedure occur automatically.
To do this requires a file in your home directory called .netrc.
The .netrc file contains login and initialization information to
be used by the auto-login process. The following variables are
used and can be separated by spaces, tabs, or new lines.
machine name
This is the name of the remote computer. The auto-login process
will search the .netrc file for a machine variable that matches
the name of the remote computer on the ftp command or as an open
command argument. Once a match is found, the next variables are
also processed until the end of file or another machine variable
is encountered.
login name
This is the username on the remote system. If this variable is
present, the auto-login process will login to the remote computer
with the given username.
password string
This is the password to be used when logging into the remote
system.
NOTE: If this variable is present in the .netrc file, ftp
will abort the auto-login process if the .netrc file is
readable by anyone but the user.
account string
This supplies an additional account password. If present, the
auto-login process will supply the string as an additional
password if required by the remote server.
macdef name
This defines a macro. This variable will function like the ftp
macdef command. A macro is defined with the specified name, its
contents begin with the next .netrc line and continue until a
null line (2 new line characters). If a macro named init is
defined, it will be executed as the last step of the auto-login
process.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $cat .netrc 3
3 machine erc830 3
3 login teacher 3
3 password secret1 3
3 machine erc780 3
3 login rharding 3
3 password secret2 3
3 $ 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
To invoke the auto-login feature, type the ftp command and enter
the name of the remote computer as an argument.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $ftp erc830 3
3 Connected to erc830. 3
3 220 erc830 Wollongong FTP Server (Ver 5.0) at Tue Oct 23 3
3 331 Password required for rharding. 3
3 230 User logged in, default directory D_1131:[RHARDING] 3
3 ftp> 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
If the .netrc file is readable by anyone other than the user, the
following error message will appear; and the connection will not
be made to the remote computer.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 $ls -l .netrc 3
3 $ftp erc830 3
3 Connected to erc830. 3
3 220 erc830 Wollongong FTP Server (Ver 5.0) at Tue Oct 23 3
3 Error - .netrc file not correct mode. 3
3 Remove password or correct code. 3
3 221 Goodbye. 3
3 ftp> 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
To correct this error, change the mode of the .netrc file so it
is not readable by other users or remove the password from the
file. This is to prevent your password from being read by an
unauthorized user.
9.4 Macros
Macros are a single instruction that a program replaces by
several, usually, more complex instructions. The ftp command to
create a macro definition is:
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: macdef macro-name ?
? ?
? macro-name - the name of the macro ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
After the macdef command is given, all subsequent lines are
stored as a macro with the name macro_def. Consecutive newline
characters or carriage returns terminate the input mode into the
macro. There is a limit of 16 defined macros and a limit of 4096
characters in all defined macros.
Sample Session:
UAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA?
3 ftp>macdef get_files 3
3 open erc780 3
3 get file_1 3
3 put result_2 3
3 close 3
3 ftp> 3
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU
In this example, the four lines of the macro can be executed
simply be entering get_files at the ftp prompt. The macro will
only exist until the current ftp session is closed.
9.5 Filename Translation
Filename conventions differ from one computer to another, and FTP
will allow you to translate the name as it is transferred. One
way is to specify the name of the file as it is to exist on the
local computer. This is done by the argument on the put or get
command.
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: put local-file [remote-file] ?
? ?
? get remote-file [local-file] ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
If you don't specify the remote-file (for the put command) or the
local-file (for the get command), the name will be the same on
both the local and remote computer. This can cause a problem if
you are not aware of it. There is an FTP command that will allow
the name to be translated automatically.
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: nmap [inpattern outpattern] ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
If no arguments are supplied, it will set or unset the filename
mapping mechanism. If arguments are specified, remote filenames
are mapped during mput (multiple file puts) and put (single file)
commands that are issued without a specified remote filename.
If arguments are specified, local filenames are mapped during
mget (multiple file gets) and get (single file) commands that are
issued without a specified local filename.
The mapping follows the pattern set by inpattern and outpattern.
Variable templating is done by including the sequences "$1",
"$2",...."$9 "in inpattern. All other characters are treated
literally and are used to determine the nmap inpattern variable
values.
For example, say the inpattern was $1.$2 and the remote filename
is mydata.data, $1 would have the value mydata and $2 would have
the value data. The outpattern determines the resulting mapped
filename. The sequences "$1", "$2",..."$9", are replaced by the
value resulting from the inpattern template. "$0" is replaced by
the original filename.
9.6 Aborting Transfers
Press the terminal interrupt key (usually Ctrl-C) to abort a file
transfer. The sending transfer will stop immediately. Receiving
transfers will be halted by FTP sending an ABOR command to the
remote server and discarding any further data that is received.
If the remote server doesn't support the ABOR protocol command
the ftp> prompt will not appear until the requested file has been
sent.
9.7 More Remote Computer Commands
These commands can be useful when working with the directories on
the remote computer.
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: cdup ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
This FTP command will change the remote machine current working
directory to the parent of the current working directory.
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: delete remote-file ?
? ?
? remote-file name of the file to delete ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
This FTP command will delete the specified file.
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: mdelete [remote-files] ?
? ?
? remote-files names of the files to delete ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
This FTP command acts as a multiple delete. It will delete all
the specified files.
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: mkdir directory-name ?
? ?
? directory-name the name of the directory to be created ?
? on the remote computer. ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
This FTP command will create a directory on the remote computer.
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
? Command Format: rmdir directory-name ?
? ?
? directory-name the name of the directory on the remote ?
? computer that will be removed. ?
EIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII?
This FTP command will remove the specified directory.
NOTE: This command will not work with some remote servers.
Workshop 10
This workshop will reinforce your understanding of the ideas
presented in this chapter. Login using the username and password
given to you by the instructor. Each student is to complete the
entire workshop.
DESK EXERCISES (10 minutes)
1. What FTP command is used to transfer more than one file
at a time? What FTP command will give a prompt to you
before each file is retrieved? Suggestion: there are
two ways
2. What is the name of the file where the auto-login
variables are found? Extra credit: Why does this file
begin with a dot (.)?
3. How can the file in question the auto-login file be
protected from unauthorized reading?
4. What do the following FTP commands do?
cdup
delete (tough question)
mdelete (ditto)
mkdir
rmdir
Continue on the next page
COMPUTER EXERCISES (30 minutes)
5. Transfer all the files from on the VAX (erc830) to the
domax1. Use only one command and use wildcards. The
username and password for the VAX will be given to you
by the instructor.
6. Transfer the files from the VAX and this time translate
the names of the files as they are transferred.
7. Create an auto-login file for the erc830 and
then do an auto-login to the VAX.
8. Logout
APPENDIX A - sh
NAME
sh, rsh - shell, the standard/restricted command programming
language
SYNOPSIS
sh [ -acefhiknrstuvx ] [ args ]
rsh [ -acefhiknrstuvx ] [ args ]
DESCRIPTION
sh is a command programming language that executes commands
read from a terminal or a file. rsh is a restricted version
of the standard command interpreter sh; it is used to set up
login names and execution environments whose capabilities
are more controlled than those of the standard shell. See
Invocation below for the meaning of arguments to the shell.
Definitions
A blank is a tab or a space. A name is a sequence of
letters, digits, or underscores beginning with a letter or
underscore. A parameter is a name, a digit, or any of the
characters *, @, #, ?, -, $, and !.
Commands
A simple-command is a sequence of non-blank words separated
by blanks. The first word specifies the name of the command
to be executed. Except as specified below, the remaining
words are passed as arguments to the invoked command. The
command name is passed as argument 0 (see exec(2)). The
value of a simple-command is its exit status if it
terminates normally, or (octal) 200+status if it terminates
abnormally (see signal(2) for a list of status values).
A pipeline is a sequence of one or more commands separated
by |. The standard output of each command but the last is
connected by a pipe(2) to the standard input of the next
command. Each command is run as a separate process; the
shell waits for the last command to terminate. The exit
status of a pipeline is the exit status of the last command.
A list is a sequence of one or more pipelines separated by
;, &, &&, or ||, and optionally terminated by ; or &. Of
these four symbols, ; and & have equal precedence, which is
lower than that of && and ||. The symbols && and || also
have equal precedence. A semicolon (;) causes sequential
execution of the preceding pipeline; an ampersand (&) causes
asynchronous execution of the preceding pipeline (i.e., the
shell does not wait for that pipeline to finish). The
symbol && (||) causes the list following it to be executed
only if the preceding pipeline returns a zero (non-zero)
exit status. An arbitrary number of new-lines may appear in
a list, instead of semicolons, to delimit commands.
A command is either a simple-command or one of the
following. Unless otherwise stated, the value returned by a
command is that of the last simple-command executed in the
command.
for name [ in word ... ] do list done
Each time a for command is executed, name is set to the
next word taken from the in word list. If in word ...
is omitted, then the for command executes the do list
once for each positional parameter that is set (see
Parameter Substitution below). Execution ends when
there are no more words in the list.
case word in [ pattern [ | pattern ] ... ) list ;; ] ... esac
A case command executes the list associated with the
first pattern that matches word. The form of the
patterns is the same as that used for file-name
generation (see File Name Generation) except that a
slash, a leading dot, or a dot immediately following a
slash need not be matched explicitly.
if list then list [ elif list then list ] ... [ else list ] fi
The list following if is executed and, if it returns a
zero exit status, the list following the first then is
executed. Otherwise, the list following elif is
executed and, if its value is zero, the list following
the next then is executed. Failing that, the else lis
is executed. If no else list or then list is executed
then the if command returns a zero exit status.
while list do list done
A while command repeatedly executes the while list and
if the exit status of the last command in the list is
zero, executes the do list; otherwise the loop
terminates. If no commands in the do list are
executed, then the while command returns a zero exit
status; until may be used in place of while to negate
the loop termination test.
(list)
Execute list in a sub-shell.
{ list; }
list is executed in the current (that is, parent)
shell.
name () { list; }
Define a function which is referenced by name. The
body of the function is the list of commands between {
and }. Execution of functions is described below (see
Execution).
The following words are only recognized as the first word of
a command and when not quoted:
if then else elif fi case esac for while until
do done {}
Comments
A word beginning with # causes that word and all the
following characters up to a new-line to be ignored.
Command Substitution
The shell reads commands from the string between two grave
accents (``) and the standard output from these commands may
be used as all or part of a word. Trailing new-lines from
the standard output are removed.
No interpretation is done on the string before the string is
read, except to remove backslashes (\) used to escape other
characters. Backslashes may be used to escape a grave
accent (`) or another backslash (\) and are removed before
the command string is read. Escaping grave accents allows
nested command substitution. If the command substitution
lies within a pair of double quotes (" ...` ...` ... "), a
backslash used to escape a double quote (\") will be
removed; otherwise, it will be left intact.
If a backslash is used to escape a new-line character
(\new-line), both the backslash and the new-line are removed
(see the later section on Quoting). In addition,
backslashes used to escape dollar signs (\$) are removed.
Since no interpretation is done on the command string before
it is read, inserting a backslash to escape a dollar sign
has no effect. Backslashes that precede characters other
than \, `, ", new-line, and $ are left intact when the
command string is read.
Parameter Substitution
The character $ is used to introduce substitutable
parameters. There are two types of parameters, positional
and keyword. If parameter is a digit, it is a positional
parameter. Positional parameters may be assigned values by
set. Keyword parameters (also known as variables) may be
assigned values by writing:
name=value [ name=value ] ...
Pattern-matching is not performed on value. There cannot be
a function and a variable with the same name.
${parameter}
The value, if any, of the parameter is substituted.
The braces are required only when parameter is followed
by a letter, digit, or underscore that is not to be
interpreted as part of its name. If parameter is * or
@, all the positional parameters, starting with $1, are
substituted (separated by spaces). Parameter $0 is set
from argument zero when the shell is invoked.
${parameter:-word}
If parameter is set and is non-null, substitute its
value; otherwise substitute word.
${parameter:=word}
If parameter is not set or is null set it to word; the
value of the parameter is substituted. Positional
parameters may not be assigned to in this way.
${parameter:?word}
If parameter is set and is non-null, substitute its
value; otherwise, print word and exit from the shell.
If word is omitted, the message "parameter null or not
set" is printed.
${parameter:+word}
If parameter is set and is non-null, substitute word;
otherwise substitute nothing.
In the above, word is not evaluated unless it is to be used
as the substituted string, so that, in the following
example, pwd is executed only if d is not set or is null:
echo ${d:-`pwd`}
If the colon (:) is omitted from the above expressions, the
shell only checks whether parameter is set or not.
The following parameters are automatically set by the shell:
# The number of positional parameters in decimal.
- Flags supplied to the shell on invocation or by
the set command.
? The decimal value returned by the last
synchronously executed command.
$ The process number of this shell.
! The process number of the last background command
invoked.
The following parameters are used by the shell:
HOME The default argument (home directory) for the cd
command.
PATH The search path for commands (see Execution
below). The user may not change PATH if
executing under rsh.
CDPATH
The search path for the cd command.
MAIL If this parameter is set to the name of a mail
file and the MAILPATH parameter is not set, the
shell informs the user of the arrival of mail in
the specified file.
MAILCHECK
This parameter specifies how often (in seconds)
the shell will check for the arrival of mail in
the files specified by the MAILPATH or MAIL
parameters. The default value is 600 seconds (10
minutes). If set to 0, the shell will check
before each prompt.
MAILPATH
A colon (:) separated list of file names. If
this parameter is set, the shell informs the user
of the arrival of mail in any of the specified
files. Each file name can be followed by % and a
message that will be printed when the
modification time changes. The default message
is you have mail.
PS1 Primary prompt string, by default "$ ".
PS2 Secondary prompt string, by default "> ".
IFS Internal field separators, normally space, tab,
and new-line.
SHACCT
If this parameter is set to the name of a file
writable by the user, the shell will write an
accounting record in the file for each shell
procedure executed. Accounting routines such as
acctcom(1) and acctcms(1M) can be used to analyze
the data collected.
SHELL When the shell is invoked, it scans the
environment (see Environment below) for this
name. If it is found and 'rsh' is the file name
part of its value, the shell becomes a restricted
shell.
The shell gives default values to PATH, PS1, PS2, MAILCHECK
and IFS. HOME and MAIL are set by login(1).
Blank Interpretation
After parameter and command substitution, the results of
substitution are scanned for internal field separator
characters (those found in IFS) and split into distinct
arguments where such characters are found. Explicit null
arguments ("" or '') are retained. Implicit null arguments
(those resulting from parameters that have no values) are
removed.
Input/Output
A command's input and output may be redirected using a
special notation interpreted by the shell. The following
may appear anywhere in a simple-command or may precede or
follow a command and are not passed on to the invoked
command; substitution occurs before word or digit is used:
<word Use file word as standard input (file
descriptor 0).
>word Use file word as standard output (file
descriptor 1). If the file does not exist it
is created; otherwise, it is truncated to zero
length.
>>word Use file word as standard output. If the file
exists output is appended to it (by first
seeking to the end-of-file); otherwise, the
file is created.
<<[-]word After parameter and command substitution are
done on word, the shell input is read up to
the first line that literally matches the
resulting word, or to an end-of-file. If,
however, - is appended to <<:
1) leading tabs are stripped from word before
the shell input is read (but after
parameter and command substitution is done
on word),
2) leading tabs are stripped from the shell
input as it is read and before each line
is compared with word, and
3) shell input is read up to the first line
that literally matches the resulting word,
or to an end-of-file.
If any character of word is quoted (see
Quoting, later), no additional processing is
done to the shell input. If no characters of
word are quoted:
1) parameter and command substitution occurs,
2) (escaped) \newline is ignored, and
3) \ must be used to quote the characters \,
$, and `.
The resulting document becomes the standard
input.
<&digit Use the file associated with file descriptor
digit as standard input. Similarly for the
standard output using >&digit.
<&- The standard input is closed. Similarly for
the standard output using >&--.
If any of the above is preceded by a digit, the file
descriptor which will be associated with the file is that
specified by the digit (instead of the default 0 or 1). For
example:
... 2>&1
associates file descriptor 2 with the file currently
associated with file descriptor 1.
The order in which redirections are specified is
significant. The shell evaluates redirections left-to-
right. For example:
... 1>xxx 2>&1
first associates file descriptor 1 with file xxx. It
associates file descriptor 2 with the file associated with
file descriptor 1 (i.e. xxx). It directs both standard
output and standard error output (stdout, stderr) to xxx.
If the order of redirections were reversed, file descriptor
2 would be associated with the terminal (assuming file
descriptor 1 had been) and file descriptor 1 would be
associated with file xxx.
Using the terminology introduced on the first page, under
Commands, if a command is composed of several simple
commands, redirection will be evaluated for the entire
command before it is evaluated for each simple command.
That is, the shell evaluates redirection for the entire
list, then each pipeline within the list, the each command
within each pipeline, then each list within each command.
If a command is followed by & the default standard input for
the command is the empty file /dev/null. Otherwise, the
environment for the execution of a command contains the file
descriptors of the invoking shell as modified by
input/output specifications.
Redirection of output is not allowed in the restricted
shell.
File Name Generation
Before a command is executed, each command word is scanned
for the characters *, ?, and [. If one of these characters
appears, the word is regarded as a pattern. The word is
replaced with alphabetically sorted file names that match
the pattern. If no file name is found that matches the
pattern, the word is left unchanged. The character . at the
start of a file name or immediately following a /, as well
as the character / itself, must be matched explicitly.
* Matches any string, including the null string.
? Matches any single character.
[...] Matches any one of the enclosed characters. A
pair of characters separated by - matches any
character lexically between the pair,
inclusive. If the first character following
the opening "[" is a "!" any character not
enclosed is matched.
Quoting
The following characters have a special meaning to the shell
and cause termination of a word unless quoted:
; & ( ) | ^ < > new-line space tab
A character may be quoted (i.e., made to stand for itself)
by preceding it with a backslash (\) or inserting it between
a pair of quote marks ('' or ""). During processing, the
shell may quote certain characters to prevent them from
taking on a special meaning. Backslashes used to quote a
single character are removed from the word before the
command is executed. The pair \newline is removed from a
word before command and parameter substitution.
All characters enclosed between a pair of single quote marks
(''), except a single quote, are quoted by the shell.
Backslash has no special meaning inside a pair of single
quotes. A single quote may be quoted inside a pair of
double quote marks (for example, "'").
Inside a pair of double quote marks (""), parameter and
command substitution occurs and the shell quotes the results
to avoid blank interpretation and file name generation. If
$* is within a pair of double quotes, the positional
parameters are substituted and quoted, separated by quoted
spaces ("$1 $2 ..."); however, if $@ is within a pair of
double quotes, the positional parameters are substituted and
quoted, separated by unquoted spaces ("$1" "$2" ...). \
quotes the characters \, `, ", and $. The pair \newline is
removed before parameter and command substitution. If a
backslash precedes characters other than \, `, ", $, and
new-line, the backslash itself is quoted by the shell.
Prompting
When used interactively, the shell prompts with the value of
PS1 before reading a command. If at any time a new-line is
typed and further input is needed to complete a command, the
secondary prompt (i.e., the value of PS2) is issued.
Environment
The environment (see environ(5)) is a list of name-value
pairs that is passed to an executed program in the same way
as a normal argument list. The shell interacts with the
environment in several ways. On invocation, the shell scans
the environment and creates a parameter for each name found,
giving it the corresponding value. If the user modifies the
value of any of these parameters or creates new parameters,
none of these affects the environment unless the export
command is used to bind the shell's parameter to the
environment (see also set -a). A parameter may be removed
from the environment with the unset command. The
environment seen by any executed command is thus composed of
any unmodified name-value pairs originally inherited by the
shell, minus any pairs removed by unset, plus any
modifications or additions, all of which must be noted in
export commands.
The environment for any simple-command may be augmented by
prefixing it with one or more assignments to parameters.
Thus:
TERM=450 cmd
and
(export TERM; TERM=450; cmd)
are equivalent (as far as the execution of cmd is
concerned).
If the -k flag is set, all keyword arguments are placed in
the environment, even if they occur after the command name.
The following first prints a=b c and c:
echo a=b c
set -k
echo a=b c
Signals
The INTERRUPT and QUIT signals for an invoked command are
ignored if the command is followed by &; otherwise signals
have the values inherited by the shell from its parent, with
the exception of signal 11 (SIGSEGV) (but see also the trap
command below). See nohup(1) for more signal handling.
Execution
Each time a command is executed, the above substitutions are
carried out. If the command name matches one of the Special
Commands listed below, it is executed in the shell process.
If the command name does not match a Special Command, but
matches the name of a defined function, the function is
executed in the shell process (note how this differs from
the execution of shell procedures). The positional
parameters $1, $2, .... are set to the arguments of the
function. If the command name matches neither a Special
Command nor the name of a defined function, a new process is
created and an attempt is made to execute the command via
exec(2).
The shell parameter PATH defines the search path for the
directory containing the command. Alternative directory
names are separated by a colon (:). The default path is
:/bin:/usr/bin (specifying the current directory, /bin, and
/usr/bin, in that order). Note that the current directory
is specified by a null path name, which can appear
immediately after the equal sign or between the colon
delimiters anywhere else in the path list. If the command
name contains a / the search path is not used; such commands
will not be executed by the restricted shell. Otherwise,
each directory in the path is searched for an executable
file. If the file has execute permission but is not an
a.out file, it is assumed to be a file containing shell
commands. A sub-shell is spawned to read it. A
parenthesized command is also executed in a sub-shell.
The location in the search path where a command was found is
remembered by the shell (to help avoid unnecessary execs
later). If the command was found in a relative directory,
its location must be re-determined whenever the current
directory changes. The shell forgets all remembered
locations whenever the PATH variable is changed or the hash
-r command is executed (see below).
Special Commands
Input/output redirection is now permitted for these
commands. File descriptor 1 is the default output location.
:
No effect; the command does nothing. A zero exit code
is returned.
. file
Read and execute commands from file and return. The
search path specified by PATH is used to find the
directory containing file.
break [ n ]
Exit from the enclosing for or while loop, if any. If
n is specified break n levels.
continue [ n ]
Resume the next iteration of the enclosing for or while
loop. If n is specified resume at the nth enclosing
loop.
cd [ arg ]
Change the current directory to arg. The shell
parameter HOME is the default arg. The shell parameter
CDPATH defines the search path for the directory
containing arg. Alternative directory names are
separated by a colon (:). The default path is <null>
(specifying the current directory). Note that the
current directory is specified by a null path name,
which can appear immediately after the equal sign or
between the colon delimiters anywhere else in the path
list. If arg begins with a / the search path is not
used. Otherwise, each directory in the path is
searched for arg. The cd command may not be executed
by rsh.
echo [ arg ... ]
Echo arguments. See echo(1) for usage and description.
eval [ arg ... ]
The arguments are read as input to the shell and the
resulting command(s) executed.
exec [ arg ... ]
The command specified by the arguments is executed in
place of this shell without creating a new process.
Input/output arguments may appear and, if no other
arguments are given, cause the shell input/output to be
modified.
exit [ n ]
Causes a shell to exit with the exit status specified
by n. If n is omitted the exit status is that of the
last command executed (an end-of-file will also cause
the shell to exit.)
export [ name ... ]
The given names are marked for automatic export to the
environment of subsequently-executed commands. If no
arguments are given, a list of all names that are
exported in this shell is printed. (Variable names
exported from a parent shell are listed only if they
have been exported again during the current shell's
execution.) Function names may not be exported.
getopts
Use in shell script to support command syntax standards
(see intro(1)); it parses positional parameters and
checks for legal options. See getopts(1) for usage and
description.
hash [ -r ] [ name ... ]
For each name, the location in the search path of the
command specified by name is determined and remembered
by the shell. The -r option causes the shell to forget
all remembered locations. If no arguments are given,
information about remembered commands is presented.
hits is the number of times a command has been invoked
by the shell process. cost is a measure of the work
required to locate a command in the search path. If a
command is found in a "relative" directory in the
search path, after changing to that directory, the
stored location of that command is recalculated.
Commands for which this will be done are indicated by
an asterisk (*) adjacent to the hits information. cost
will be incremented when the recalculation is done.
newgrp [ arg ... ]
Equivalent to exec newgrp arg .... See newgrp(1M) for
usage and description.
pwd
Print the current working directory. See pwd(1) for
usage and description.
read [ name ... ]
One line is read from the standard input and, using the
internal field separator, IFS (normally space or tab),
to delimit word boundaries, the first word is assigned
to the first name, the second word to the second name,
etc., with leftover words assigned to the last name.
Lines can be continued using \new-line. Characters
other than new-line can be quoted by preceding them
with a backslash. These backslashes are removed before
words are assigned to names, and no interpretation is
done on the character that follows the backslash. The
return code is 0 unless an end-of-file is encountered.
readonly [ name ... ]
The given names are marked readonly and the values of
these names may not be changed by subsequent
assignment. If no arguments are given, a list of all
readonly names is printed.
return [ n ]
Causes a function to exit with the return value
specified by n. If n is omitted, the return status is
that of the last command executed.
set [ --aefhkntuvx [ arg ... ] ]
-a
Mark variables which are modified or created for
export.
-e Exit immediately if a command exits with a non-
zero exit status.
-f Disable file name generation.
-h Locate and remember function commands as functions
are defined (function commands are normally
located when the function is executed).
-k All keyword arguments are placed in the
environment for a command, not just those that
precede the command name.
-n Read commands but do not execute them.
-t Exit after reading and executing one command.
-u Treat unset variables as an error when
substituting.
-v Print shell input lines as they are read.
-x Print commands and their arguments as they are
executed.
-- Do not change any of the flags; useful in setting
$1 to -.
Using + rather than - causes these flags to be turned
off. These flags can also be used upon invocation of
the shell. The current set of flags may be found in
$-. The remaining arguments are positional parameters
and are assigned, in order, to $1, $2, .... If no
arguments are given the values of all names are
printed.
shift [ n ]
The positional parameters from $n+1 ... are renamed $1
.... If n is not given, it is assumed to be 1.
test
Evaluate conditional expressions. See test(1) for usage
and description.
times
Print the accumulated user and system times for
processes run from the shell.
trap [ arg ] [ n ] ...
The command arg is to be read and executed when the
shell receives signal(s) n. (Note that arg is scanned
once when the trap is set and once when the trap is
taken.) Trap commands are executed in order of signal
number. Any attempt to set a trap on a signal that was
ignored on entry to the current shell is ineffective.
An attempt to trap on signal 11 (memory fault) produces
an error. If arg is absent all trap(s) n are reset to
their original values. If arg is the null string this
signal is ignored by the shell and by the commands it
invokes. If n is 0 the command arg is executed on exit
from the shell. The trap command with no arguments
prints a list of commands associated with each signal
number.
type [ name ... ]
For each name, indicate how it would be interpreted if
used as a command name.
ulimit [ n ]
Impose a size limit of n blocks on files written by the
shell and its child processes (files of any size may be
read). If n is omitted, the current limit is printed.
Each user may lower the ulimit, but only a super-user
(see su(1M)) can raise a ulimit.
umask [ nnn ]
The user file-creation mask is set to nnn (see
umask(1)). If nnn is omitted, the current value of the
mask is printed.
unset [ name ... ]
For each name, remove the corresponding variable or
function. The variables PATH, PS1, PS2, MAILCHECK and
IFS cannot be unset.
wait [ n ]
Wait for a background process whose process ID is n and
report its termination status. If n is omitted, all
the shell's currently active background processes are
waited for and the return code will be zero.
Invocation
If the shell is invoked through exec(2) and the first
character of argument zero is -, commands are initially read
from /etc/profile and from $HOME/.profile, if such files
exist. Thereafter, commands are read as described below,
which is also the case when the shell is invoked as /bin/sh.
The flags below are interpreted by the shell on invocation
only. Note that unless the -c or -s flag is specified, the
first argument is assumed to be the name of a file
containing commands, and the remaining arguments are passed
as positional parameters to that command file:
-c string If the -c flag is present commands are read from
string.
-s If the -s flag is present or if no arguments
remain commands are read from the standard input.
Any remaining arguments specify the positional
parameters. Shell output (except for Special
Commands) is written to file descriptor 2.
-i If the -i flag is present or if the shell input
and output are attached to a terminal, this shell
is interactive. In this case TERMINATE is ignored
(so that kill 0 does not kill an interactive
shell) and INTERRUPT is caught and ignored (so
that wait is interruptible). In all cases, QUIT
is ignored by the shell.
-r If the -r flag is present the shell is a
restricted shell.
The remaining flags and arguments are described under the
set command above.
rsh Only
rsh is used to set up login names and execution environments
whose capabilities are more controlled than those of the
standard shell. The actions of rsh are identical to those
of sh, except that the following are disallowed:
changing directory (see cd(1)),
setting the value of $PATH,
specifying path or command names containing /,
redirecting output (> and >>).
The restrictions above are enforced after .profile is
interpreted.
A restricted shell can be invoked in one of the following
ways: (1) rsh is the file name part of the last entry in the
/etc/passwd file (see passwd(4)); (2) the environment
variable SHELL exists and rsh is the file name part of its
value; (3) the shell is invoked and rsh is the file name
part of argument 0; (4) the shell is invoked with the -r
option.
When a command to be executed is found to be a shell
procedure, rsh invokes sh to execute it. Thus, it is
possible to provide to the end-user shell procedures that
have access to the full power of the standard shell, while
imposing a limited menu of commands; this scheme assumes
that the end-user does not have write and execute
permissions in the same directory.
The net effect of these rules is that the writer of the
.profile has complete control over user actions, by
performing guaranteed setup actions and leaving the user in
an appropriate directory (probably not the login directory).
The system administrator often sets up a directory of
commands (i.e., /usr/rbin) that can be safely invoked by
rsh. Some systems also provide a restricted editor red.
EXIT STATUS
Errors detected by the shell, such as syntax errors, cause
the shell to return a non-zero exit status. If the shell is
being used non-interactively execution of the shell file is
abandoned. Otherwise, the shell returns the exit status of
the last command executed (see also the exit command above).
FILES
/etc/profile
$HOME/profile
/tmp/sh*
/dev/null
SEE ALSO
acctcom(1), cd(1), echo(1), env(1), ksh(1), login(1),
pwd(1), test(1), umask(1).
acctcms(1M), newgrp(1M), su(1M) in the UMAX V
Administrator's Reference Manual.
dup(2), exec(2), fork(2), pipe(2), signal(2), ulimit(2),
wait(2), a.out(4), passwd(4), profile(4), environ(5) in the
UMAX V Programmer's Reference Manual.
CAVEATS
Words used for filenames in input/output redirection are not
interpreted for filename generation (see File Name
Generation, above). For example, cat file1 > a* will create
a file named a*.
Because commands in pipelines are run as separate processes,
variables set in a pipeline have no effect on the parent
shell.
If the error message cannot fork, too many processes is
displayed, try using the wait(1) command to clean up the
background processes. If this does not help, the system
process table is probably full or there are too many active
foreground processes. (There is a limit to the number of
process IDs associated with a login and to the number of
which the system can keep track.)
BUGS
If a command is executed, and a command with the same name
is installed in a directory in the search path before the
directory where the original command was found, the shell
will continue to exec the original command. Use the hash
command to correct this situation.
If the current directory or one above it is moved, pwd may
not give the correct response. Use the cd command with a
full path name to correct this situation.
Not all the processes of a 3- or more-stage pipeline are
children of the shell, and thus cannot be waited for.
For wait n, if n is not an active process id, all the
shell's currently active background processes are waited for
and the return code will be zero.
APPENDIX B - ftp
$man ftp
NAME
ftp - Internet file transfer program
SYNOPSIS
ftp [ -v ] [ -d ] [ -i ] [ -n ] [ -g ] [ host ]
DESCRIPTION
ftp is the user interface to the DARPA File Transfer
Protocol. The program transfers files to and from a remote
network site.
The client host with which ftp is to communicate can be
specified on the command line. In this case, ftp immediately
attempts to establish a connection to an FTP server on that
host; otherwise, ftp enters its command interpreter and
waits for instruction, displaying the prompt ftp>.
ftp recognizes the following commands:
! [ command [ args ] ]
Invoke an interactive shell on the local machine.
If there are arguments, the first is taken to be a
command to execute directly, with the rest of the
arguments as its arguments.
$ macro-name [ args ]
Execute the macro-name that was defined with
the macdef command. Arguments are passed to the
macro unglobbed.
account [ passwd ]
Supply a supplemental password required by a
remote system for access to resources once a login
has been successfully completed. If no argument
is included, the user will be prompted for an
account password in a non-echoing input mode.
append local-file [ remote-file ]
Append a local file to a file on the remote
machine. If remote-file is left unspecified, the
local file name is used to name the remote file
after being altered by any ntrans or nmap setting.
File transfer uses the current settings for type,
format, mode, and structure.
ascii Set the file transfer type to network ASCII. This
is the default type.
bell Sound a bell after each file transfer command is
completed.
binary Set the file transfer type to support binary image
transfer.
bye Terminate the FTP session with the remote server
and exit ftp.
case Toggle remote computer file name case mapping
during mget commands. When case is on (default is
off), remote computer file names with all letters
in upper case are written in the local directory
with the letters mapped to lower case.
cd remote-directory
Change the working directory on the remote machine
to remote-directory.
cdup Change the remote machine working directory to the
parent of the current remote machine working
directory.
close Terminate the FTP session with the remote server,
and return to the command interpreter. Any
defined macros are erased.
cr Toggle carriage return stripping during ASCII type
file retrieval. Records are denoted by a carriage
return/linefeed sequence during ASCII type file
transfer. When cr is on (the default), carriage
returns are stripped from this sequence to conform
with the UNIX single linefeed record delimiter.
Records on non-UNIX remote systems may contain
single linefeeds; when an ASCII type transfer is
made, these linefeeds may be distinguished from a
record delimiter only when cr is off.
delete remote-file
Delete the file remote-file on the remote machine.
debug [ debug-value ]
Toggle debugging mode. If an optional debug-value
is specified, it is used to set the debugging
level. When debugging is on, ftp prints each
command sent to the remote machine, preceded by
the string --> .
dir [ remote-directory ] [ local-file ]
Print the contents of directory, remote-directory,
and, optionally, place the output in local-file.
If no directory is specified, the current working
directory on the remote machine is used. If no
local file is specified, or local-file is -,
output comes to the terminal.
disconnect
A synonym for close.
form format
Set the file transfer form to format. The default
format is file.
get remote-file [ local-file ]
Retrieve the remote-file and store it on the local
machine. If the local file name is not specified,
it is given the same name it has on the remote
machine, subject to alteration by the current
case, ntrans, and nmap settings. The current
settings for type, form, mode, and structure are
used while transferring the file.
glob Toggle filename expansion for mdelete, mget and
mput. If globbing is turned off with glob, the
file name arguments are taken literally and not
expanded. Globbing for mput is done as in csh(1).
For mdelete and mget, each remote file name is
expanded separately on the remote machine and the
lists are not merged. Expansion of a directory
name is likely to be different from expansion of
the name of an ordinary file: the exact result
depends on the foreign operating system and FTP
server, and can be previewed by doing
"mls remote-files -". NOTE: mget and mput are
not meant to transfer entire directory subtrees of
files. That can be done by transferring a tar(1)
archive of the subtree (in binary mode).
hash Toggle number-sign (#) printing for each data
block transferred. The size of a data block i
1024 bytes.
help [ command ]
Print a description of command. With no argument,
ftp prints a list of the known commands.
lcd [ directory ]
Change the working directory on the local machine.
If no directory is specified, changes to the
user's home directory.
ls [ remote-directory ] [ local-file ]
Print an abbreviated listing of the contents of a
directory on the remote machine. If remote-
directory is left unspecified, the current working
directory is used. If no local file is specified,
the output is sent to the terminal.
macdef macro-name
Define a macro. Subsequent lines are stored as
the macro-name; a null line (consecutive
newline characters in a file or carriage returns
from the terminal) terminates macro input mode.
There is a limit of 16 macros and 4096 total
characters in all defined macros. Macros remain
defined until a close command is executed. The
macro processor interprets "$" and "\" as special
characters. A "$" followed by a number (or
numbers) is replaced by the corresponding argument
on the macro invocation command line. A "$"
followed by an "i" signals that macro processor
that the executing macro is to be looped. On the
first pass "$i" is replaced by the first argument
on the macro invocation command line, on the
second pass it is replaced by the second argument,
and so on. A "\" followed by any character is
replaced by that character. Use the "\" to
prevent special treatment of the "$".
mdelete [ remote-files ]
Delete the specified files on the remote machine.
mdir remote-files local-file
Like dir, except multiple remote files may be
specified. If interactive prompting is on, ftp
will prompt the user to verify that the last
argument is indeed the target local file for
receiving mdir output.
mget remote-files
Expand the remote-files on the remote machine and
do a get for each file name thus produced. See
glob for details on the filename expansion.
Resulting file names will then be processed
according to case, ntrans, and nmap settings.
Files are transferred into the local working
directory, which can be changed with
"lcd directory"; new local directories can be
created with "! mkdir directory".
mkdir directory-name
Make a directory on the remote machine.
mls remote-files local-file
Like ls, except multiple remote files may be
specified. If interactive prompting is on, ftp
will prompt the user to verify that the last
argument is indeed the target local file for
receiving mls output.
mode [ mode-name ]
Set the file transfer mode to mode-name. The
default mode is stream.
mput local-files
Expand wild cards in the list of local files given
as arguments and do a put for each file in the
resulting list. See glob for details of filename
expansion. Resulting file names will then be
processed according to ntrans and nmap settings.
nmap [ inpattern outpattern ]
Set or unset the filename mapping mechanism. If
no arguments are specified, the filename mapping
mechanism is unset. If arguments are specified,
remote filenames are mapped during mput commands
and put commands issued without a specified remote
target filename. If arguments are specified,
local filenames are mapped during mget commands
and get commands issued without a specified local
target filename. This command is useful when
connecting to a non-UNIX remote computer with
different file naming conventions or practices.
The mapping follows the pattern set by inpattern
and outpattern. inpattern is a template for
incoming filenames (which may have already been
processed according to the ntrans and case
settings). Variable templating is accomplished by
including the sequences "$1", "$2", ..., "$9" in
inpattern. Use "\" to prevent this special
treatment of the "$" character. All other
characters are treated literally, and are used to
determine the nmap inpattern variable values. For
example, given inpattern $1.$2 and the remote file
name mydata.data, $1 would have the value mydata,
and $2 would have the value data. The outpattern
determines the resulting mapped filename. The
sequences "$1", "$2", ..., "$9" are replaced by
any value resulting from the inpattern template.
The sequence "$0" is replaced by the original
filename. Additionally, the sequence
"[seq1,seq2]" is replaced by seq1 if seq1 is not a
null string; otherwise it is replaced by seq2.
For example, the command "nmap $1.$2.$3
[$1,$2].[$2,file]" would yield the output filename
myfile.data for input filenames myfile.data and
myfile.data.old, myfile.file for the input
filename myfile, and myfile.myfile for the input
filename .myfile. Spaces may be included in
outpattern, as in the example:
nmap $1 | sed "s/ *$//" > $1
Use the "\" character to prevent special treatment
of the "$", "[", "]", and "," characters.
ntrans [ inchars [ outchars ] ]
Set or unset the filename character translation
mechanism. If no arguments are specified, the
filename character translation mechanism is unset.
If arguments are specified, characters in remote
filenames are translated during mput commands and
put commands issued without a specified remote
target filename. If arguments are specified,
characters in local filenames are translated
during mget commands and get commands issued
without a specified local target filename. This
command is useful when connecting to a non-UNIX
remote computer with different file naming
conventions or practices. Characters in a
filename matching a character in inchars are
replaced with the corresponding character in
outchars. If the character's position in inchars
is longer than the length of outchars, the
character is deleted from the file name.
open host [ port ]
Establish a connection to the specified host's FTP
server. An optional port number can be supplied,
in which case, ftp attempts to contact an FTP
server at that port. If the auto-login option is
on (default), ftp also attempts to automatically
log the user in to the FTP server (see below).
prompt Toggle interactive prompting. Interactive
prompting occurs during multiple file transfers to
allow the user to selectively retrieve or store
files. If prompting is turned off (default), any
mget or mput transfers all files and mdelete will
delete all files.
proxy ftp-command
Execute an ftp command on a secondary control
connection. This command allows simultaneous
connection to two remote FTP servers for
transferring files between the two servers. The
first proxy command should be an open, to
establish the secondary control connection. Enter
the command "proxy ?" to see other ftp commands
executable on the secondary connection. The
following commands behave differently when
prefaced by proxy: open will not define new
macros during the auto-login process, close will
not erase existing macro definitions, get and mget
transfer files from the host on the primary
control connection to the host on the secondary
control connection, and put, mput, and append
transfer files from the host on the secondary
control connection to the host on the primary
control connection. Third party file transfers
depend upon support of the FTP protocol PASV
command by the server on the secondary control
connection.
put local-file [ remote-file ]
Store a local file on the remote machine. If
remote-file is left unspecified, the local file
name is used in naming the remote file, after
processing according to any ntrans or nmap
settings. File transfer uses the current settings
for type, format, mode, and structure.
pwd Print the name of the current working directory on
the remote machine.
quit A synonym for bye.
quote arg1 arg2 ...
The arguments specified are sent, verbatim, to the
remote FTP server.
recv remote-file [ local-file ]
A synonym for get.
remotehelp [ command-name ]
Request help from the remote FTP server. If a
command-name is specified, it is supplied to the
server as well.
rename [ from ] [ to ]
Rename, on the remote machine, the file from to
the file to.
reset Clear reply queue. This command re-synchronizes
command/reply sequencing with the remote FTP
server. Resynchronization may be necessary
following a violation of the FTP protocol by the
remote server.
rmdir directory-name
Delete a directory on the remote machine.
runique Toggle storing of files on the local system with
unique filenames. If a file already exists with a
name equal to the target local filename for a get
or mget command, a ".1" is appended to the name.
If the resulting name matches another existing
file, a ".2" is appended to the original name. If
this process continues up to ".99", an error
message is printed, and the transfer does not take
place. The generated unique filename will be
reported. Note that runique will not affect local
files generated from a shell command (see below).
The default value is off.
send local-file [ remote-file ]
A synonym for put.
sendport Toggle the use of PORT commands. By default, ftp
attempts to use a PORT command when establishing a
connection for each data transfer. The use of PORT
commands can prevent delays when performing
multiple file transfers. If the PORT command
fails, ftp uses the default data port. When the
use of PORT commands is disabled, no attempt is
made to use them for each data transfer. This is
useful for certain FTP implementations that do
ignore PORT commands but wrongly indicate they
have been accepted.
status Show the current status of ftp.
struct [ struct-name ]
Set the file transfer structure to struct-name.
The default structure is stream.
sunique Toggle storing of files on remote machine under
unique file names. Remote FTP server must support
the FTP protocol STOU command for successful
completion. The remote server will report a
unique name. Default value is off.
tenex Set the file transfer type to that needed to talk
to TENEX machines.
trace Toggle packet tracing.
type [ type-name ]
Set the file transfer type to type-name. If no
type-name is specified, the current type is
printed. The default type is network ascii.
user-name [ password ] [ account ]
The user identifies him/herself to the remote FTP
server. If the password is not specified and the
server requires it, ftp prompts the user for it
(after disabling local echo). If an account field
is not specified, and the FTP server requires it,
the user is prompted for it. If an account field
is specified, an account command will be relayed
to the remote server after the login sequence is
completed if the remote server did not require it
for logging in. Unless ftp is invoked with
"auto-login" disabled, this process is done
automatically on initial connection to the FTP
server.
verbose Toggle verbose mode. In verbose mode, all
responses from the FTP server are displayed to the
user. In addition, if verbose is on, when a file
transfer completes, statistics regarding the
efficiency of the transfer are reported. By
default, verbose is on.
? [ command ]
A synonym for help.
Command arguments that have embedded spaces can be quoted
with double quote (") marks.
ABORTING A FILE TRANSFER
To abort a file transfer, use the terminal interrupt key
(usually <ctrl>C). Sending transfers will be immediately
halted. Receiving transfers will be halted by sending a FTP
protocol ABOR command to the remote server, and discarding
any further data received. The speed at which this is
accomplished depends upon the remote server's support for
ABOR processing. If the remote server does not support the
ABOR command, an ftp> prompt will not appear until the
remote server has completed sending the requested file.
The terminal interrupt key sequence will be ignored when ftp
has completed any local processing and is awaiting a reply
from the remote server. A long delay in this mode may
result from the ABOR processing described above, or from
unexpected behavior by the remote server, including
violations of the FTP protocol. If the delay results from
unexpected remote server behavior, the local ftp program
must be killed by hand.
FILE NAMING CONVENTIONS
Files specified as arguments to ftp commands are processed
according to the following rules.
1. If the file name is -, the standard input (for reading)
or the standard output (for writing) is used.
2. If the first character of the file name is a bar |, the
remainder of the argument is interpreted as a shell
command. ftp then forks a shell, using popen(3S) with
the argument supplied, and reads (writes) from the
stdout (stdin). If the shell command includes spaces,
the argument must be quoted; for example, "| ls -lt". A
particularly useful example of this mechanism is
"dir | more".
3. Failing the above checks, if globbing is enabled, local
file names are expanded according to the rules used in
the csh(1); see the glob command. If the ftp command
expects a single local file (e.g., put), only the first
filename generated by the globbing operation is used.
4. For mget commands and get commands with unspecified
local file names, the local filename is the remote
filename, which may be altered by a case, ntrans, or
nmap setting. The resulting filename may then be
altered if runique is on.
5. For mput commands and put commands with unspecified
remote file names, the remote filename is the local
filename, which may be altered by a ntrans or nmap
setting. The resulting filename may then be altered by
the remote server if sunique is on.
FILE TRANSFER PARAMETERS
The FTP specification identifies many parameters that can
affect a file transfer. The type can be one of ascii, image
(binary), ebcdic, and local byte size (for PDP-10's and
PDP-20's mostly). ftp supports the ascii and image types of
file transfer, plus local byte size 8 for tenex mode
transfers.
ftp supports only the default values for the remaining file
transfer parameters: mode, form, and struct.
OPTIONS
Options can be specified at the command line, or to the
command interpreter.
The -v (verbose on) option forces ftp to show all responses
from the remote server, as well as report on data transfer
statistics.
The -n option restrains ftp from attempting "auto-login"
upon initial connection. If auto-login is enabled, ftp
checks the netrc file in the user's home directory for an
entry describing an account on the remote machine. If no
entry exists, ftp will prompt for the remote machine login
name (default is the user identity on the local machine),
and, if necessary, prompt for a password and an account with
which to login.
The -i option turns off interactive prompting during
multiple file transfers.
The -d option enables debugging.
The -g option disables file name globbing.
THE .netrc FILE
The .netrc file contains login and initialization
information used by the "auto-login" process. It resides in
the user's home directory. The following tokens are
recognized; they may be separated by spaces, tabs, or new-
lines:
machine name
Identify a remote machine name. The auto-login process
searches the .netrc file for a machine token that
matches the remote machine specified on the ftp command
line or as an open command argument. Once a match is
made, the subsequent .netrc tokens are processed,
stopping when the end of file is reached or another
machine token is encountered.
login name
Identify a user on the remote machine. If this token
is present, the "auto-login" process will initiate a
login using the specified name.
password string
Supply a password. If this token is present, the
"auto-login" process will supply the specified string
if the remote server requires a password as part of the
login process. Note that if this token is present in
the .netrc file, ftp will abort the "auto-login"
process if the .netrc is readable by anyone besides the
user.
account string
Supply an additional account password. If this token
is present, the "auto-login" process will supply the
specified string if the remote server requires an
additional account password, or the "auto-login"
process will initiate an ACCT command if it does not.
macdef name
Define a macro. This token functions like the ftp
macdef command functions. A macro is defined with the
specified name; its contents begin with the next .netrc
line and continue until a null line (consecutive new-
line characters) is encountered. If a macro named init
is defined, it is automatically executed as the last
step in the "auto-login" process.
SEE ALSO
csh(1).
ftpd(1M) in the UMAX V Administrator's Reference Manual.
BUGS
Correct execution of many commands depends upon proper
behavior by the remote server.
An error in the treatment of carriage returns in the 4.2BSD
UNIX ASCII-mode transfer code has been corrected. This
correction may result in incorrect transfers of binary files
to and from 4.2BSD servers using the ascii type. Avoid this
problem by using the binary image type.
APPENDIX C - C Compiler
NAME
cc - C compiler
SYNOPSIS
cc [ option ] ... file ...
DESCRIPTION
The cc command invokes the C language compiler. This C
compiler is an advanced, optimizing compiler that accepts a
complete implementation of the C programming language. For
a more complete description of the compiler, see "C
Language" and "Compiler and C Language" in the UMAX V
Programmer's Guide.
Files with a .c suffix are taken to be C language source
programs. The compiler processes every C language source
file to produce a corresponding object file with the same
file name and a .o suffix. Files with a .s suffix are taken
to be assembly language source programs. These are
assembled to produce a corresponding object file with the
same file name and a .o suffix. Files with a suffix other
than .c and .s are assumed to be object files (usually
produced by an earlier compilation or assembly) or C-
compatible libraries. These files, together with any object
code produced by the compiler, are linked in the order they
were specified to produce an executable program file named
a.out.
If only one input file with a .c or .s suffix is supplied,
the compiler automatically deletes the object file output
produced from that input file after the executable program
file a.out is created.
The cc options that modify the behavior described above are:
-A Cause ASCII assembler output to be generated and
automatically piped to the assembler. The default
is for direct generation of object code. The -A
option is the same as the -q nodirect_code option.
-Bpath Run the compiler program contained in pathccom. If
-B is specified with no path, then the default path
is assumed to be /lib/o and the compiler program in
/lib/occom is run. If no -B option is specified,
then the compiler program in /lib/ccom is run.
-c Compile only. Produce object file output, even if
there was only one source file.
-C Retain comments during the macro preprocessor pass.
-Dname=def
Define symbol name to be string def, as if by a
#define statement. If =def is omitted, define name
to be 1.
-E Run only the macro preprocessor, process only input
files with the .c suffix; send the result of this
pass to the standard output.
-g Generate special symbol table data for sdb(1) or
cdb(1) and pass the -g flag to the link editor.
-G Cause object code to be directly generated by the
compiler, bypassing the intermediate steps of
producing assembly code and assembling it to
produce object code. This is the default. The -G
option is the same as the -q direct_code option.
-Idir dir is a directory name. Search for #include files
whose names do not begin with / first in the
directory containing the source file, then in dir,
and then in a list of standard defaults. Multiple
-I options can establish a hierarchy of #include
file directories.
-o output
Name the final, executable output file output
instead of a.out. Note the space between the -o
and the file name.
-O Perform optimizations which speed up the generated
code. Also, perform any space optimizations which
do not impact code speed. See also the -q option.
-p Prepare to generate an execution profile using
prof(1). Include special profiling code that
counts how many times each routine is called. If
linking occurs, use a special startup routine that
calls monitor(3C) and produces a mon.out file upon
termination. Uses special profiling versions of
standard libraries found in /usr/lib/libp/lib*.a.
NOTE: use of the MARK macro (see prof(5)) requires
the -A option of cc.
-pg Prepare to generate an execution profile using
gprof(1). Include special profiling code that
counts how many times each function is called and
how much time is spent in each. If linking occurs,
use a special startup function that calls
monstartup and produces a gmon.out file upon
termination. Uses special profiling versions of
standard libraries found in /usr/lib/libp/lib*.a.
NOTE: Use of the MARK macro (see prof(5)) requires
the -A option of cc.
-P Run all .c files through the preprocessing step,
putting the result in the corresponding output file
with a .i suffix.
-R Make initialized variables shared and read-only (by
passing the -r option to the assembler).
-S Generate only assembly language output, putting it
in one or more files that have the source file name
and an .s suffix.
-Uname Undefine symbol name to remove its default
definition.
-v Report the names of all subprocesses invoked in the
compiled program, and their arguments. This option
shows any files that are linked automatically and
the current compiler, assembler, and link editor
options.
-w Suppress warning diagnostics.
-Wc,arg
-Wa,arg
-Wl,arg Pass option arg to the compiler (see "C Compiler
Internal Options" in the "Compiler and C Language"
chapter in the UMAX V Programmer's Guide),
assembler (see as(1)), or linker (see ld(1)),
respectively.
The following options are intended to provide more detailed
control over the generated code and action of the compiler.
In general, they should only be used for special situations.
-q qualifier
-q qualifier=arg
Modify the generated code of the compiler to
reflect various special requirements of a program.
Qualifiers include the following:
align_text, noalign_text
Enable alignment of text segments on boundaries
that allows the burst mode of systems equipped
with APCs (Advanced Dual Processor Cards,
utilizing the NS32332 CPU chip) to be most
effectively used. The default option is
-q noalign_text, unless the -q optimize=time
option is specified.
xpc, apc, dpc
Generate code optimized for a system equipped
with XPCs (Extended Performance Dual Processor
Cards, utilizing the NS32532 CPU chip), APCs
(Advanced Dual Processor Cards, utilizing the
NS32332 CPU chip), or DPCs (Dual Processor
Cards, utilizing the NS32032 CPU chip). If the
-q xpc option is specified, then the
preprocessor symbol ns32532 is defined and code
optimal for the NS32532 is generated. If the
-q apc option is specified, then the
preprocessor symbol ns32332 is defined and the
-q align_text option is enabled. If the -q dpc
option is specified, then the preprocessor
symbol ns32032 is defined and the
-q noalign_text option is enabled. If neither
-q xpc nor -q apc nor -q dpc is specified, then
the default option is either -q xpc or -q apc
or -q dpc , depending upon whether the system
upon which the compiler is running is equipped
with XPCs, APCs, or DPCs, respectively. Code
generated with these options will work on all
XPCs, APCs, and DPCs.
asmdir=prefix
crt0dir=prefix
lddir=prefix
Overrides the defaults for the locations of
as(1) (the assembler), the relevant startup
routine (either crt0.o, mcrt0.o, or gcrt0.o),
and ld(1) (the link editor). The default
values for these are asmdir=/bin/,
crt0dir=/lib/ (if the startup routine is crt0.o
or mcrt0.o), crt0dir=/usr/lib/ (if the startup
routine is gcrt0.o), and lddir=/bin/.
compiler_registers, nocompiler_registers
Enable or disable compiler allocation of local
variables to registers beyond those specified
by register storage class specifications. The
default option is -q compiler_registers. The
-q nocompiler_registers option should only be
used when code is written to depend on the
existence of non-register class variables in
memory.
direct_code, nodirect_code
Enable or disable the direct generation of code
by the compiler. When enabled, the compiler
will directly generate object code, bypassing
the intermediate steps of producing assembly
code and assembling it to produce the object
code. The -q nodirect_code option (same as the
-A option) should only be needed if the source
file contains asm statements. The
-q direct_code option (same as the -G option)
is enabled by default. The -q nodirect_code
option is enabled if the -R option is
specified.
enter_exits, noenter_exits
Generate enter and exit instructions at
subroutine start and end. Enter and exit
instructions make stack tracing by debuggers
possible. The -q noenter_exits option is
enabled by default, unless the -g option is
used.
extensions, noextensions
extensions=parallel
extensions=microtasking
Specifies which language extensions will be
recognized. The -q extensions=parallel option
specifies that extensions which support
parallel programming are recognized. This
includes shared memory declarations and in-line
code generation for spin lock routines.
Consult the section "C Parallel Programming
Extensions" in Chapter 18, Compiler and C
Language in the UMAX V Programmer's Guide. The
-q extension=microtasking option specifies that
extensions which support microtasking are
recognized. This includes the
-q extension=parallel extensions, and also
specifies that the microtasking library and an
alternate version of crt0.o are to be used by
the load step. The -q extensions option is
equivalent to -q extension=microtasking. The
default option is -q noextensions.
limitfregs, nolimitfregs
Use or don't use the new NS32532 double
precision floating point registers f1, f3, f5,
f7. This flag is valid only in conjunction with
the -q xpc flag. The default value for this
flag is -q limitfregs (the new registers are
not used). The double precision registers f1,
f3, f5, f7 do not exist on APCs and DPCs, and
code that uses these registers will not work on
APCs and DPCs.
includes, noincludes
Look or don't look for C language include files
in the standard directory /usr/include.
-q noincludes specifies there is no standard
location for the include files. The default
value is -q includes.
long_case, nolong_case
Enable or disable the generation of case
statements using a full four byte displacement.
The -q nolong_case option is the default,
allowing case statements to span 8 Kilobytes.
The -q long_case option allows case statements
to span 16 Megabytes. This should only be
needed in unusual circumstances.
long_jump, nolong_jump
Enable or disable the generation of jumps with
four byte displacements when the assembler is
unable to resolve them in 1 byte. This option
only has effect when direct code generation is
not enabled. The default option,
-q nolong_jump, allows branches to span up to
_8 Kilobytes. The -q long_jump option will
allow branches to span up to _16 Megabytes.
loops, noloops
Enable or disable loop optimizations. These
optimizations include loop-invariant hoisting
and strength reduction. The default option is
-q noloops.
optimize, nooptimize
optimize=none,optimize=standard,optimize=time,optimize=space
Specify the level of optimization. The
-q optimize option is equivalent to the
-q optimize=standard. The -q nooptimize option
is equivalent to -q optimize=none. The -O
option is equivalent to -q optimize=standard.
The -q optimize=standard option enables a set
of optimizations that do not take an excessive
time to generate and do not overly favor space
over time or vice versa. The -q optimize=time
option enables optimizations which may take
longer to recognize but should yield a program
that takes minimal time. This option enables
-q align_text, -q loops, and -q novolatile. If
any of these options are inappropriate, they
may be overridden by the appropriate -q noxxx
option. The -q optimize=space option enables
optimizations which may take longer to generate
but should yield a program which takes minimal
space. This option enables
-q preload_constants and -q tail_merge. The
default option is -q optimize=none.
preload_constants, nopreload_constants
Enable or disable the linking of constant
values and addresses that are frequently
referenced in the source code at the start of a
program. This option saves space; it may save
execution time if the constants and addresses
are also referenced frequently during
execution. The -q nopreload_constants option is
the default; the -q preload_constants option is
enabled by the -O option.
reg_params, noreg_params
Pass the first two parameters to a subroutine
in registers rather than on the stack. The
-q noreg_params option is the default. The
standard libraries provided with the system
assume -q noreg_params and will not work with
object files built with the -q reg_params
option.
sbfixed, nosbfixed
Enable or disable the use of the NS32000 sb
register when generating immediate addresses.
The -q sbfixed option is the default.
signed_bit_fields, nosigned_bit_fields
Enable or disable making bit fields in
structures of type int, short, and char to be
signed. The default option,
-q nosigned_bit_fields, is to make all fields
unsigned.
small_enums, nosmall_enums
Enable or disable the allocation of each enum
type as the smallest predefined type that can
represent all of the values that are listed
(that is values of type char, short, int,
unsigned char, unsigned short, or unsigned that
are used in the enum statement). The default
option, -q nosmall_enums, allocates an enum
type as an int.
standard_library, nostandard_library
Allows the compiler to replace calls to
standard libc routines with equivalent in-line
code. The default option is
-q nostandard_library, unless the
-q optimize=time option is specified.
tail_merge, notail_merge
Enable or disable branch-tail merging, an
optimization which reduces code size by sharing
common portions of then and else clauses or of
case switches. The -q tail_merge option is
enabled by default, and disabled when -O is
specified.
volatile, novolatile
Disable or enable additional optimization on
the assumption that memory never changes except
as the result of explicit store operations. The
default option, -q volatile, disables these
optimizations. The -q novolatile option should
be used when all variables that can be modified
asynchronously (e.g., by signal handlers) have
type volatile. Asynchronous modification could
happen, for example, with signals, device
drivers, and parallel processes accessing
shared memory. The current default is
-q novolatile. In the future, the goal is to
have -q volatile the default value.
FILES
file.c input file
file.o object file
a.out linked output
/lib/ccom compiler
/lib/occom backup compiler
/lib/crt0.o runtime startoff
/lib/mcrt0.o startoff for profiling
/lib/libc.a standard library, see intro(3)
/usr/libp/lib*.a profiling libraries, see intro(3)
/usr/include standard directory for #include files
mon.out file produced for analysis by prof(1)
SEE ALSO
adb(1), as(1), cdb(1), gprof(1), ld(1), prof(1), sdb(1),
a.out(4), monitor(3C).
cflow(1) in the UMAX V User's Reference Manual.
"C Language" and "Compiler and C Language" in the UMAX V
cflow(1) in the UMAX V User's Reference Manual.
"C Language" and "Compiler and C Language" in the UMAX V
Programmer's Guide.
B. W. Kernighan and D. M. Ritchie, The C Programming
Language. Prentice-Hall, 1978.
DIAGNOSTICS
The diagnostics produced by C itself are intended to be
self-explanatory. Occasional messages may be produced by
the assembler or link editor.
APPENDIX D - FORTRAN Compiler
$man f77
NAME
f77 - Fortran-77 compiler
SYNOPSIS
f77 [ options ] file [ options ] [ files ] ...
DESCRIPTION
The f77 compiler is an advanced, optimizing Fortran-77
compiler that accepts a complete implementation of the
standard Fortran language defined by ANSI standard X3.9-
1978. It also has extensions to support VAX Fortran
functionality and parallel programming. The Fortran-77
compiler accepts any or none of the options described
following, and one or more input file names. Files and
options can be mixed in any order. Any differences between
4.2 and V are noted in the text.
Files that have an f or F extension are taken to be
Fortran-77 language source programs. The compiler processes
every Fortran-77 source file to produce a corresponding
object file with the same file name and an o extension.
Source files that have an F extension are passed through the
C language macro preprocessor before being compiled by the
f77 compiler. Files that have an e extension are assumed to
be EFL (Extended Fortran Language) files, which are passed
through the efl preprocessor before being compiled by the
Fortran-77 compiler. Files that have an r extension are
taken to be Ratfor files and passed through the ratfor
preprocessor before being compiled. Files that have an s
extension are assumed to be assembly language source
programs. These are assembled to produce a corresponding
object file with the same file name and an o extension.
Files with extensions other than f, F, e, r, and s are
assumed to be Fortran-compatible libraries, or object files
such as those files produced by an earlier compilation or
assembly. These files, together with any object code
produced during the compilation, are loaded to produce an
executable program file named aout.
If only one input file with an f, F, e, r, or s extension is
supplied, the compiler automatically deletes the object file
output produced from that input file after executable
program file aout has been created.
All unrecognized options and all file names with extensions
other than .f, .F, .e, .r, .c are passed to the loader. For
assembler options, see as(1); for loader options, see ld(1).
The f77 options are:
-Bprefix Run the compiler program contained in file
prefixfcom. If prefix is not given,
/usr/lib/ofcom is the default compiler used.
-c Compile only. Produce object file output (even if
there was only one source file) and do not load
the program after compiling it.
-Dname=def
Define symbol name to be string def, when running
the C language preprocessor, as if by a #define
statement. If =def is omitted, defines name to be
1 while running the C preprocessor.
-Estring Pass option(s) string to the efl preprocessor when
processing input files that have the e extension.
-F Generate only Fortran language output from the
ratfor or efl preprocessor, placing it in a file
that has the source file name and the f extension,
but do not run the Fortran-77 compiler.
-g Generate special symbol table data for the sdb(1)
debugger (or the optional debugger), and pass the
-lg flag to the loader.
-Ipath Include source files from the directory named path
when running the C language preprocessor. When
compiling source files named with the F extension,
search for #include files (whose names do not
begin with /) first in the directory containing
the source file, then in the directory path, and
then in a list of standard defaults. Multiple -I
options can establish a hierarchy of #include file
directories.
-i2 Make the default length of integer constants and
variables, and all logical quantities, be short.
Complementary option -i4 is the default, which
calls for long integer variables and constants.
-m Apply the M4 macro preprocessor to each EFL or
Ratfor source file before passing it through the
efl or ratfor preprocessor.
-O Perform optimizations that speed up the generated
code; also perform any space optimizations that do
not impact code speed. See also the -q qualifier
options.
-o output Name the final, executable output file output
rather than aout.
-onetrip Generate object code that executes the range of
every do loop at least once, even if the initial
value of the loop index exceeds the limit value.
-p Prepare to generate an execution profile using
prof(1). Include special profiling code that
counts how many times each routine is called. If
loading occurs, use a special startup routine that
calls monitor(3) and produces a monout file upon
termination. Use a special profiling library
instead of the standard C library.
-pg Generate an execution profile using gprof.
Include special profiling code that counts how
many times each routine is called. If loading
occurs, use a special startup routine that calls
monitor(3) and produces one or more gmon.pid upon
termination. A profiling version of the standard
library is used.
-R Make initialized variables shared and read-only
(by passing the -r option to the assembler).
-Rstring Pass option(s) string to the ratfor preprocessor
when processing input files that have an r
extension.
-S Generate assembly language output for each source
file, but do not assemble it. Assembler output
for a source file with the extension f, F, e, r,
or c is put in a file with the same name and a s
extension.
-U Do not convert uppercase letters to lowercase
letters. By default Fortran programs are
converted to lowercase letters except within
character string constants.
-u Disable automatic data typing and, instead, make
the default type of a variable the undefined type.
-v Report the names of all subprocesses invoked by
the compiler and their arguments.
-w Suppress warning diagnostics.
-w66 Recognized only for compatibility with the
Portable Fortran-77 Compiler, which used this
option to suppress warnings about Fortran-66
features encountered during compilation. The
Fortran-77 compiler does not flag language
elements that are unique to Fortran-66.
-W[a c l], arg
Pass option arg to the assembler, compiler, or
linker, as specified respectively by -Wa, arg,
-Wc, arg, or -Wl, arg. The internal options for
the f77 compiler include implementation options
used to reconfigure the compiler for alien
operating environments, and debugging options used
for testing compiler software. These options
should never be used in normal operation; they are
described in the Fortran-77 Manual.
-q qualifier[=arg]
The qualifier options provide more detailed
control over the generated code and action of the
compiler. They modify the generated code of the
compiler to reflect various special requirements
of a program, and in general should only be used
for special situations. The qualifier options
deal with architecture, optimization selections,
file configuration, and Fortran language
extensions. In this listing they are grouped by
category. Both the qualifiers and any arguments,
which have compiler-defined values, can be
abbreviated to their minimum number of unique
characters. The qualifiers are:
portable
apc, apc01, apc02, dpc, xpc[,2arg], host_is_target,
These qualifiers select generation of code
that is compatible with Multimax systems
having APC DPC or XPC (National
Semiconductor NS32xxx-based) processor
boards. The default is to generate code
appropriate for the machine on which the
compiler is running. (Differences between
generated APC and DPC code are primarily in
alignment optimization.)
apc The apc qualifier selects APC01 code
and the libm_apc.a math library.
apc01 The apc01 qualifier is the same as the
apc qualifier. It is equivalent to
the obsoleted switch combination,
-q apc -q nofpa.
apc02 The apc02 qualifier selects APC02 code
(with Cone instructions) and uses the
libm_fpa.a math library. This is
equivalent to the obsoleted switch
combination, -q apc -q fpa.
dpc The dpc qualifier selects code
optimized for a DPC system, and uses
the libm_apc.a library.
xpc[,arg]
The xpc qualifier generates code
optimized for XPC systems, using the
libm_xpc.a math library. Since xpc
permits access of 4 additional
floating point (fp) registers and uses
floating point instructions that do
not exist for APC and DPC boards, code
compiled using this option may not be
portable to APC and DPC systems. xpc
accepts the arguments limitfregs and
nolimitfregs. -q xpc,limitfregs
assures code compatibility with APC
and DPC systems, selecting the
libm_apc.a math library rather than
libm_xpc.a and suppressing the usage
of some double-precision floating
point registers that are available to
XPC systems; only 4 double-precision
float registers are used.
-q xpc,nolimitfregs permits all
floating point registers to be used,
and uses the libm_xpc.a math library.
host_is_target
The host_is_target qualifier optimizes
code for the system performing the
compilation. No attempt is made to
preserve portability. This is default
behavior.
portable
The portable qualifier generates code
that is portable across all Multimax
APC, DPC, and XPC systems. A
universal math library, libm_apc.a, is
used. Only optimizations that are
explicitly portable are used.
Produced code is portable to APC and
DPC systems even if compiled on an XPC
system, since only 4 double-precision
float registers are used.
align_text, noalign_text
Enable or disable alignment of text segments
on boundaries to optimize burst mode on
Multimax systems having APC s. The default
is noalign_text, unless optimize=time is
enabled.
asmdir=prefix
Use the assembler located in the prefixas
file instead of the default assembler,
/bin/as.
compiler_registers, nocompiler_registers
Enable or disable compiler allocation of
local variables to registers beyond those
specified by register storage class
specifications. The default is
compiler_registers. nocompiler_registers
should only be used when code is written to
depend on the existence of non-register
class variables in memory.
crt0dir=prefix
Use the prefixcrt0.o startup file instead of
the default startup file, /lib/crt0.o.
d_lines, nod_lines
Enable or disable the recognition of any
comment line, beginning with a D, as a code
line. The default is nod_lines.
direct_code, nodirect_code
Enable or disable the direct generation of
code by the compiler. When enabled, the
compiler directly generates object code,
bypassing the intermediate steps of
producing assembly code and assembling it to
produce the object code. The nodirect_code
qualifier should only be needed if the
source file contains asm statements.
direct_code is enabled by default.
nodirect_code is enabled if the -R option is
specified.
extensions[=arg], noextensions
Enable or disable the specification of
Fortran extensions. The default qualifier
is noextensions. The available arguments
are:
berkeley_f77 Supports the standard UNIX
f77. This is equivalent to
noextensions.
extended_f77 Supports an extension to f77
that allows Fortran programs
written for VAX/VMS to be
compiled on Multimax systems.
This is the default when the
-q extensions qualifier is
given without an argument.
parallel Recognizes the extensions
that support parallel
programming, including shared
memory declarations and
spinlocks in-line. This does
not change the value of an
earlier specified
berkeley_f77 or extended_f77
selection.
lddir=prefix
Use the link editor in prefixld instead of
the default, /bin/ld.
long_case, nolong_case
Enable or disable the generation of case
statements using a full four-byte
displacement. nolong_case is the default,
allowing case statements to span 4
Kilobytes. long_case allows case statements
to span 2 Megabytes. This should only be
needed in unusual circumstances.
long_jump, nolong_jump
Enable or disable the generation of jumps
with four-byte displacements when the
assembler is unable to resolve them in one
byte. The default, nolong_jump, allows
branches to span up to _8 Kilobytes.
long_jump allows branches to span up to _16
Megabytes. Direct code generation selects
one-, two-, or four-byte displacement as
appropriate, regardless of the setting of
this option.
loops, noloops
Enable or disable loop optimizations. These
optimizations include loop-invariant
hoisting and strength reduction. The
default is noloops.
optimize[=arg], nooptimize
Enable or disable different levels of
optimization. The default is optimize=none.
The available arguments are:
none Enable no special optimizations.
none is equivalent to nooptimize.
space Enable optimizations which may
take longer to generate but which
should produce a program that
requires minimal space. This
argument also enables
preload_constants and tail_merge.
standard Enable a set of optimizations
that do not take an excessive
amount of time to generate and
which do not favor space over
time (or vice versa).
time Enable optimizations which may
take longer to recognize but
which should produce a program
that requires minimal execution
time. This argument also enables
align_text, loops, and
novolatile.
preload_constants, nopreload_constants
Enable or disable the loading of constant
values and addresses that are frequently
referenced in the source code at the start
of a program. This option saves space; it
may save execution time if the constants and
addresses are also referenced frequently
during execution. no_preload_constants is
the default; preload_constants is enabled by
the -O option.
single_lib, nosingle_lib
Enable or disable the use of single
precision math routines for certain built-in
functions when the functions are called with
single precision arguments. The single
precision versions offer significantly
increased speed with almost no reduction in
accuracy. single_lib is enabled by default.
tail_merge, notail_merge
Enable or disable branch-tail merging, an
optimization that reduces code size by
sharing common portions of then and else
clauses or of case switches. tail_merge is
disabled by default.
volatile, novolatile
Enable or disable additional optimization on
the assumption that memory never changes
except as the result of explicit store
operations. The default is volatile, unless
optimize=time is selected. novolatile,
which enables the optimizations, is
available only when optimize=time is
selected. novolatile should only be used
when it is clear that no variables can be
modified asynchronously. Asynchronous
modification could happen, for example, with
signals, device drivers, or parallel
processes accessing shared memory.
RESTRICTIONS
The -q flag and its qualifier options replace the following
options, which are no longer supported:
-A Replaced by -q nodirect_code.
-G Replaced by -q direct_code.
-H Replaced by -q notail_merge.
-J Replaced by -q long_jump.
-T Replaced by -q loops.
-V Replaced by -q novolatile.
FILES
./fort[pid].? temporary fortran process files
a.out loaded output file
file.[fFresc] input file
file.o object file
gmon.[pid] file produced for analysis by monitor(3)
mon.out file produced for analysis by prof(1)
/lib/cpp C preprocessor
/lib/libc.a C library
/lib/cpp C preprocessor
/lib/libc.a C library
/usr/lib/fcom Fortran compiler
/usr/lib/libFBERK.a combined libF77.a, libI77.a, and
libU77.a library
/usr/lib/libFBERK_p.a profiling combined Berkeley function
library
/usr/lib/libFORT.a combined libFBERK.a and libX77.a
library
/usr/lib/libFORT_p.a profiling combined extended Berkeley
function
/usr/lib/libm_apc.a standard NS32081 code math library
/usr/lib/libm_fpa.a math library for APC02 systems with
Cone processor
/usr/lib/libm_xpc.a XPC system math library (8 float-
register, NS32381)
SEE ALSO
as(1), cc(1), ld(1), m4(1), prof(1), sdb(1), cdb(1X),
efl(1F), fpr(1F) fsplit(1F) ratfor(1F), struct(1F),
intro(3F) epf(9F),
Fortran-77 Manual.
American National Standard Programming Language Fortran,
ANSI X3.9-1978.
APPENDIX E - lint
$man lint
NAME
lint - a C program checker
SYNOPSIS
lint [ option ] ... file ...
DESCRIPTION
lint attempts to detect features of the C program files that
are likely to be bugs, non-portable, or wasteful. It also
checks type usage more strictly than the compilers. Among
the things that are currently detected are unreachable
statements, loops not entered at the top, automatic
variables declared and not used, and logical expressions
whose value is constant. Moreover, the usage of functions
is checked to find functions that return values in some
places and not in others, functions called with varying
numbers or types of arguments, and functions whose values
are not used or whose values are used but none returned.
Arguments whose names end with .c are taken to be C source
files. Arguments whose names end with .ln are taken to be
the result of an earlier invocation of lint with either the
-c or the -o option used. The .ln files are analogous to .o
(object) files that are produced by the cc(1) command when
given a .c file as input. Files with other suffixes are
warned about and ignored.
lint will take all the .c, .ln, and llib-lx.ln (specified by
-lx) files and process them in their command line order. By
default, lint appends the standard C lint library (llib-
lc.ln) to the end of the list of files. However, if the -p
option is used, the portable C lint library (llib-port.ln)
is appended instead. When the -c option is not used, the
second pass of lint checks this list of files for mutual
compatibility. When the -c option is used, the .ln and the
llib-lx.ln files are ignored.
Any number of lint options may be used, in any order,
intermixed with file-name arguments. The following options
are used to suppress certain kinds of complaints:
-a Suppress complaints about assignments of long values
to variables that are not long.
-b Suppress complaints about break statements that
cannot be reached. (Programs produced by lex(1) or
yacc(1) will often result in many such complaints.)
-h Do not apply heuristic tests that attempt to intuit
bugs, improve style, and reduce waste.
-u Suppress complaints about functions and external
variables used and not defined, or defined and not
used. (This option is suitable for running lint on
a subset of files of a larger program).
-v Suppress complaints about unused arguments in
functions.
-x Do not report variables referred to by external
declarations but never used.
The following arguments alter lint's behavior:
-lx Include additional lint library llib-lx.ln. For
example, a lint version of the Math Library llib-lm.ln
can be included by inserting -lm on the command line.
This argument does not suppress the default use of
llib-lc.ln. These lint libraries must be in the
assumed directory. This option can be used to
reference local lint libraries and is useful in the
development of multi-file projects.
-n Do not check compatibility against either the standard
or the portable lint library.
-p Attempt to check portability to other dialects (IBM and
GCOS) of C. Along with stricter checking, this option
causes all non-external names to be truncated to eight
characters and all external names to be truncated to
six characters and one case.
-c Cause lint to produce a .ln file for every .c file on
the command line. These .ln files are the product of
lint's first pass only, and are not checked for inter-
function compatibility.
-o lib
Cause lint to create a lint library with the name
llib-llib.ln. The -c option nullifies any use of the
-o option. The lint library produced is the input that
is given to lint's second pass. The -o option simply
causes this file to be saved in the named lint library.
To produce a llib-llib.ln without extraneous messages,
use of the -x option is suggested. The -v option is
useful if the source file(s) for the lint library are
just external interfaces (for example, the way the file
llib-lc is written). These option settings are also
available through the use of "lint comments" (see
below).
The -D, -U, and -I options of cc(1) and cpp(1) and the -g
and -O options of cc are also recognized as separate
arguments. The -g and -O options are ignored, but, by
recognizing these options, lint's behavior is closer to that
of the cc command. Other options are warned about and
ignored. The pre-processor symbol "lint" is defined to
allow certain questionable code to be altered or removed for
lint. Therefore, the symbol "lint" should be thought of as
a reserved word for all code that is planned to be checked
by lint.
Certain conventional comments in the C source will change
the behavior of lint:
/*NOTREACHED*/
at appropriate points stops comments about unreachable
code. (This comment is typically placed just after
calls to functions like exit(2).)
/*VARARGSn*/
suppresses the usual checking for variable numbers of
arguments in the following function declaration. The
data types of the first n arguments are checked; a
missing n is taken to be 0.
/*ARGSUSED*/
turns on the -v option for the next function.
/*LINTLIBRARY*/
at the beginning of a file shuts off complaints about
unused functions and function arguments in this file.
This is equivalent to using the -v and -x options.
lint produces its first output on a per-source-file basis.
Complaints regarding included files are collected and
printed after all source files have been processed.
Finally, if the -c option is not used, information gathered
from all input files is collected and checked for
consistency. At this point, if it is not clear whether a
complaint stems from a given source file or from one of its
included files, the source file name will be printed
followed by a question mark.
The behavior of the -c and the -o options allows for
incremental use of lint on a set of C source files.
Generally, one invokes lint once for each source file with
the -c option. Each of these invocations produces a .ln
file which corresponds to the .c file, and prints all
messages that are about just that source file. After all
the source files have been separately run through lint, it
is invoked once more (without the -c option), listing all
the .ln files with the needed -lx options. This will print
all the inter-file inconsistencies. This scheme works well
with make(1); it allows make to be used to lint only the
source files that have been modified since the last time the
set of source files were linted.
FILES
/usr/lib/lint[12] first and second passes
/usr/lib/llib-lc.ln declarations for C Library
functions (binary format; source is
in /usr/lib/llib-lc)
/usr/lib/llib-port.ln declarations for portable functions
(binary format; source is in
/usr/lib/llib-port)
/usr/lib/llib-lm.ln declarations for Math Library
functions (binary format; source is
in /usr/lib/llib-lm.ln)
/usr/tmp/*lint* temporaries
SEE ALSO
cc(1), cpp(1), lex(1), make(1), yacc(1), tmpnam(3S).
BUGS
exit(2), longjmp(3C), and other functions that do not return
are not understood; this causes various lies.
APPENDIX F - cb
$man cb
NAME
cb - C program beautifier
SYNOPSIS
cb [ -s ] [ -j ] [ -l leng ] [ file ... ]
DESCRIPTION
The cb comand reads C programs either from its arguments or
from the standard input, and writes them on the standard
output with spacing and indentation that display the
structure of the code. Under default options, cb preserves
all user new-lines.
cb accepts the following options.
-s Canonicalizes the code to the style of Kernighan
and Ritchie in The C Programming Language.
-j Causes split lines to be put back together.
-l leng Causes cb to split lines that are longer than
leng.
SEE ALSO
cc(1).
The C Programming Language. Prentice-Hall, 1978.
BUGS
Punctuation that is hidden in preprocessor statements will
cause indentation errors.
APPENDIX G - ar
$man ar
NAME
ar - archive and library maintainer for portable archives
SYNOPSIS
ar key [ posname ] afile [ name ] ...
DESCRIPTION
The ar command maintains groups of files combined into a
single archive file. Its main use is to create and update
library files as used by the link editor. It can be used,
though, for any similar purpose. The magic string and the
file headers used by ar consist of printable ASCII
characters. If an archive is composed of printable files,
the entire archive is printable.
When ar creates an archive, it creates headers in a format
that is portable across all machines. The portable archive
format and structure is described in detail in ar(4). The
archive symbol table (described in ar(4)) is used by the
link editor (ld(1)) to effect multiple passes over libraries
of object files in an efficient manner. An archive symbol
table is only created and maintained by ar when there is at
least one object file in the archive. The archive symbol
table is in a specially named file which is always the first
file in the archive. This file is never mentioned or
accessible to the user. Whenever the ar command is used to
create or update the contents of such an archive, the symbol
table is rebuilt. The s option described below will force
the symbol table to be rebuilt. The symbol table holds a
maximum of 20,000 symbols.
Unlike command options, the command key is a required part
of ar's command line. The key (which may begin with a -) is
formed with one of the following letters: drqtpmx.
Arguments to the key, alternatively, are made with one of
more of the following set: vuaibcls. posname is an archive
member name used as a reference point in positioning other
files in the archive. afile is the archive file. The names
are constituent files in the archive file. The meanings of
the key characters are as follows:
d Delete the named files from the archive file.
r Replace the named files in the archive file. If the
optional character u is used with r, then only those
files with dates of modification later than the archive
files are replaced. If an optional positioning
character from the set aib is used, then the posname
argument must be present and specifies that new files
are to be placed after (a) or before (b or i) posname.
Otherwise new files are placed at the end.
q Quickly append the named files to the end of the
archive file. Optional positioning characters are
invalid. The command does not check whether the added
members are already in the archive. This option is
useful to avoid quadratic behavior when creating a
large archive piece-by-piece. Unchecked, the file may
grow exponentially up to the second degree.
t Print a table of contents of the archive file. If no
names are given, all files in the archive are tabled.
If names are given, only those files are tabled.
p Print the named files in the archive.
m Move the named files to the end of the archive. If a
positioning character is present, then the posname
argument must be present and, as in r, specifies where
the files are to be moved.
x Extract the named files. If no names are given, all
files in the archive are extracted. In neither case
does x alter the archive file.
The meanings of the key arguments are as follows:
v Give a verbose file-by-file description of the making
of a new archive file from the old archive and the
constituent files. When used with t, give a long
listing of all information about the files. When used
with x, precede each file with a name.
c Suppress the message that is produced by default when
afile is created.
l Place temporary files in the local (current working)
directory, rather than in the default temporary
directory, /tmp.
s Force the regeneration of the archive symbol table even
if ar is not invoked with a command which will modify
the archive contents. This command is useful to
restore the archive symbol table after the strip(1)
command has been used on the archive.
SEE ALSO
ld(1), lorder(1), strip(1), tmpnam(3S), a.out(4), ar(4).
"The Common Object File Format" in the UMAX V Programmer's
Guide.
BUGS
If the same file is mentioned twice in an argument list, it
may be put in the archive twice.
NAME
ar - common archive file format
DESCRIPTION
The archive command ar(1) combines several files into one.
Archives are used mainly as libraries to be searched by the
link editor ld(1).
Each archive begins with the archive magic string:
#define ARMAG "!<arch>\n" /* magic string */
#define SARMAG 8 /* length of magic string */
Each archive that contains common object files (see
a.out(4)) includes an archive symbol table. The link editor
ld uses the symbol table to determine which archive members
Each archive that contains common object files (see
a.out(4)) includes an archive symbol table. The link editor
ld uses the symbol table to determine which archive members
must be loaded during the link edit process. The archive
symbol table (if it exists) is always the first file in the
archive (but is never listed) and is automatically created
and updated by ar.
Following the archive magic string are the archive file
members. Each file member is preceded by a file member
header in the following format:
#define ARFMAG "`\n" /* header trailer string */
struct ar_hdr { /* file member header */
char ar_date[12]; /* file member date */
member name */
char ar_gid[6]; /* file member group
identification */
char ar_mode[8]; /* file member mode
(octal) */
char ar_size[10]; /* file member size */
char ar_fmag[2]; /* header trailer string */
};
All information in the file member headers is in printable
ASCII . The numeric information in the headers is stored as
decimal numbers (except for ar_mode, which is in octal).
Thus, if the archive contains printable files, the archive
itself is printable.
The ar_name field is blank-padded and terminated with a
slash (/). The ar_date field is the modification date of
the file at the time it is inserted into the archive.
Common format archives can be moved from system to system as
long as the portable archive command ar is used.
Each archive file member begins on an even byte boundary; a
newline is inserted between files if necessary.
Nevertheless the size given reflects the actual size of the
file exclusive of padding.
Notice there is no provision for empty areas in an archive
file.
If the archive symbol table exists, the first file in the
archive has a zero length name (that is, ar_name[0] == '/').
The contents of this file are:
The number of symbols. Length: 4 bytes.
The array of offsets into the archive file. Length: 4
bytes * "the number of symbols".
The name string table. Length: ar_size - (4 bytes *
("the number of symbols" + 1)).
The string table contains exactly as many null-terminated
strings as there are elements in the offsets array. Each
offset from the array is associated with the corresponding
name from the string table (in order). The names in the
string table are all the defined global symbols found in the
common object files in the archive. Each offset is the
location of the archive header for the associated symbol.
SEE ALSO
ar(1), ld(1), strip(1), ldahread(3X), ldfcn(4), a.out(4).
CAVEATS
strip removes all archive symbol entries from the header.
The archive symbol entries must be restored with the ts
option of ar command before the archive can be used with the
link editor ld.
INDEX
netrc file..............................................................................93
profile..................................................................................1
HOME variable.............................................................................1
Object programs..........................................................................10
