The RCS MINI-HOWTO

The RCS MINI-HOWTO
Robert Kiesling
v1.4, 14 August 1997

This document covers basic installation and usage of RCS, the GNU
Revision Control System, under Linux. It also covers the installation
of the diff(1) and diff3(1) utilities, which are necessary for RCS to
operate. This document may be reproduced freely, in whole or in part,
provided that any usage of this document conforms to the general copy
right notice of the HOWTO series of the Linux Documentation Project.
See the file COPYRIGHT for details. Send all complaints, suggestions,
errata, and any miscellany to [email protected], so I can keep
this document as complete and up to date as possible.
______________________________________________________________________

Table of Contents

1. Overview of RCS.

2. System requirements.

3. Compiling RCS from Source.

4. Creating and maintaining archives.

5. (TT

6. Revision histories.

7. Including RCS data in working files.

8. RCS and

______________________________________________________________________

1. Overview of RCS.

RCS, the revision control system, is a suite of programs that tracks
changes in text files and controls shared access to files in work
group situations. It is generally used to maintain source code
modules. It lends itself to tracking revisions of document files as
well.

RCS was written by Walter F. Tichy and Paul Eggert. The latest
version which has been ported to Linux is RCS Version 5.7. There is
also a semi-official, threaded version available. Much of the
information in this HOWTO is taken from the RCS man pages.

RCS includes the rcs(1) program, which controls RCS archive file
attributes, ci(1) and co(1), which check files in and out of RCS
archives, ident(1), which searches RCS archives by keyword
identifiers, rcsclean(1), a program to clean up files that are not
being worked on or haven't changed, rcsdiff(1), which runs diff(1) to
compare the revisions, rcsmerge(1), which merges two RCS branches into
a single working file, and rlog(1), which prints RCS log messages.

Files archived by RCS may be text of any format, or binary if the diff
program used to generate change files handles 8-bit data. Files may
optionally include identification strings to aid in tracking by
ident(1). RCS uses the utilities diff(1) and diff3(3) to generate the
change files between revisions. A RCS archive consists of the initial
revision of a file, which is version 1.1, and a series of change
files, one for each revision. Each time a file is checked out of an
archive with co(1), edited, and checked back into the archive with
ci(1), the version number is increased, for example, to 1.2, 1.3, 1.4,
and so on for successive revisions.

The archives themselves commonly reside in a ./RCS subdirectory,
although RCS has other options for archive storage.

For an overview of RCS, see the rcsintro(1) manual page.

2. System requirements.

RCS needs diff(1) and diff3(3) to generate the context diff files
between revisions. The diff utilities suite needs to be installed on
your system, and when you install RCS, the software will check for its
presence.

Precompiled diffutils binaries are available at:

ftp://sunsite.unc.edu/pub/Linux/utils/text/diffutils-2.6.bin.ELF.tar.gz

and its mirror sites. If you need to compile diff(1), et al., from
source, it is located at:

ftp://prep.ai.mit.edu/pub/gnu/diffutils-2.7.tar.gz

and its mirror sites.

You will also need to have the ELF libraries installed on your system
if you want to install pre-built binaries. See the ELF-HOWTO for
further details.

3. Compiling RCS from Source.

Get the source distribution of RCS Version 5.7. It is available at

ftp://sunsite.unc.edu/pub/Linux/devel/vc/rcs-5.7.src.tar.gz

and its mirrors. After you have unpacked the archive into your source
tree, you need to configure RCS for your system. This is done via the
configure script in the source directory, which you need to execute
first. This will generate a Makefile and the appropriate conf.sh for
your system. You can then type

make install

which will build the binaries. At some point you may need to su to
root so the binaries can be installed in the correct directories.

4. Creating and maintaining archives.

The program rcs(1) does the work or creating archives and modifying
their attributes. A summary of rcs(1) options may be found in the
rcs(1) manual page.

The easiest way to create an archive is first to mkdir RCS in the
current directory, then initialize the archive with the
rcs -i name_of_work_file

command. This creates and archive with the name
./RCS/name_of_work_file,v and requests a text message describing the
archive, but it does not deposit any revisions in the archive. You
can turn on or off strict archive locking with the commands

rcs -L name_of_work_file

and

rcs -U name_of_work_file

respectively. There are other options for controlling access to the
archive, setting its format, and setting revision numbers, which are
covered in the rcs(1) manual page.

5. ci(1) and co(1) .

ci(1) and co(1) are the commands used to check files in and out of
their RCS archives. The ci(1) command may also be used to a check a
file both in and out of an archive. In their simplest forms, ci(1)
and co(1) take only the name of the working file.

ci name_of_work_file

and

co name_of_work_file

The command form

ci -l name_of_work_file

checks in the file with locking enabled, and

co -l name_of_work_file

is performed automatically. That is, ci -l checks the file out again
with locking enabled.

ci -u name_of_work_file

checks the file into the archive, and checks it out again with locking
disabled. In all cases, the user is prompted for a log message.

ci(1) will also create a RCS archive if one does not exist already.

If you don't specify a revision, ci(1) increments the version number
of the last revision locked in the archive, and appends the revised
working file to it. If you specify a revision on an existing branch,
it must be higher than the existing revision numbers. ci(1) will also
create a new branch if you specify the revision of a branch which does
not exist. See the ci(1) and co(1) man pages for details.

ci(1) and co(1) have various options for interactive and non-
interactive use. Again, see the ci(1) and co(1) man pages for
details.

6. Revision histories.

The rlog(1) program provides information about the archive file and
the logs of each revision stored in it. A command like

rlog work_file_name

will print the version history of the file, each revision's creation
date and userids of author and the person who locked the file. You
can specify archive attributes and revision parameters to view.

7. Including RCS data in working files.

co(1) maintains a list of keywords of the RCS database which are
expanded when the working file is checked out. The keyword $Id$ in a
document will expand to a string which contains the file name,
revision number, the date checked out, the author, the revision
status, and the locker, if any. Including the keyword $Log$ will
expand to the document's revision history log.

These and other keywords may be used as search criteria of the RCS
archive. See the ident(1) man page for further details.

8. RCS and emacs(1) Version Control.

The Version Control facility of emacs(1) works as a front end to RCS.
This information applies specifically to Version 19.34 of GNU Emacs,
which is provided with the major Linux distributions. When editing a
file with emacs(1) which is registered with RCS, the command vc-
toggle-read-only (bound to C-x C-q by default) will check a file in to
the emacs's Version Control, and then into RCS. Emacs will open a
buffer where you can type a log message to be included in the RCS log.
When you are finished typing a log entry, type C-c C-c to terminate
your input and proceed with the check-in process.

If you have selected strict locking for the file with RCS, you must
re-lock the file for editing by emacs(1). You can check the file out
for emacs's Version Control with the command % in buffer-menu mode.

For more information, see the GNU Emacs Manual and the Emacs info
pages.