FTP mini-HOWTO
Matthew Borowski (
[email protected] )
v0.2, 9 January 2000
How to use ftp clients and servers
______________________________________________________________________
Table of Contents
1. Preamble
1.1 Contacting Me
1.2 Legalities and Distribution
1.3 History of this document
2. About FTP
3. Beginner's guide to using ftp
3.1 Running the
3.2 Logging into an FTP server
3.3 File transfer types
3.4 Navigating and listing directories
3.5 Downloading and uploading files
3.6 Running shell commands
3.7 Hash marks and tick
3.8 Other ftp commands
4. Console FTP clients
4.1 NcFTP
4.2 lukemftp
4.3 lftp
4.4 cftp
4.5 yafc
5. X Window FTP clients
5.1 gFTP
5.2 WXftp
5.3 LLNL XDIR and XFTP
5.4 guiftp
6. FTP Servers
6.1 How an FTP Server works
6.2 Help with FTP Servers
6.2.1 WU-FTPD
6.2.2 ProFTPD
______________________________________________________________________
1. Preamble
This document was written by Matthew Borowski for the Linux
Documentation Project. I have not yet finished adding everything I
want to add. There will be a section with information on operating an
FTP server.
1.1. Contacting Me
Please contact me if you have any additions or changes for this
document. Please do not ask for technical support -- you may purchase
Unix consulting and support through my company, WorldServe, or you can
ask for help on newsgroups such as comp.os.linux.*. Please also keep
in mind that I can only understand English and Farsi.
1.2. Legalities and Distribution
This document is Copyright 1999 by Matthew Borowski. You may freely
distribute this document as long as the copyright notice remains
unaltered. If you distribute this HOWTO as part of a commercial
product, I would like to recieve a copy, but this is not required. If
you wish to distribute a modified or translated version of this
document, please contact me first for permission.
1.3. History of this document
� 991203: FTP HOWTO first written. Still a work-in-progress.
2. About FTP
FTP (File Transfer Protocol) is a client/server protocol that allows a
user to transfer files to and from a remote network site. It works
with TCP and is most commonly used on the Internet, although it can
also be used on a LAN.
An FTP site is a computer that is running FTP server software (also
known an FTP daemon, or ftpd). A public ftp site can usually be
accessed by anybody by logging in as anonymous or ftp. There are many
excellent public ftp sites that make repositories of free Unix
software available. By learning how to use FTP, you give yourself
access to an indespensible resource.
Private FTP sites require a user name or password. If you have a shell
account with your ISP, you may be able to access your files via FTP
(contact your system administrator to check on this).
An FTP client is the userland application that provides access to FTP
servers. There are many FTP clients available. Some are graphical, and
some are text-based.
FTP was first developed by the University of California, Berkeley for
inclusion in 4.2BSD (Berkeley Unix). The RFC (Request for Comments) is
available at .
3. Beginner's guide to using ftp
A quick guide to using ftp.
The standard ftp program is the original ftp client. It comes standard
with most Linux distributions. It first appeared in 4.2BSD, which was
developed by the University of California, Berkeley.
3.1. Running the ftp program
It's easy to use ftp. Let's say you want to connect to the anonymous
ftp site metalab.unc.edu, to download the latest Linux kernel source.
At the command line, type:
$ ftp metalab.unc.edu
The ftp program will attempt to connect to metalab.unc.edu. Another
way to do this is to run ftp from the command line with no parameters,
and use the open command, with the site name as an argument:
$ ftp
ftp> open metalab.unc.edu
3.2. Logging into an FTP server
When you connect to an FTP site, it will ask you for a login (pressing
enter will log in as your local user name, in this case, foo: We log
in as anonymous or ftp, to get to the public archive.
220 helios.oit.unc.edu FTP server (Version wu-2.6.0(2) Wed Nov 17 14:44:12
EST 1999) ready.
Name (metalab.unc.edu:foo):
Now, we enter a complete e-mail address as the password (this is what
most public FTP sites request).
331 Guest login ok, send your complete e-mail address as password.
Password:
After a successful login, the following information is given to us:
Remote system type is UNIX.
Using binary mode to transfer files.
ftp>
3.3. File transfer types
After you log in to an ftp site, ftp will print out the file transfer
type. In our case, it is binary. Binary mode transfers the files, bit
by bit, as they are on the FTP server. Ascii mode, however, will
download the text directly. You can type ascii or binary to switch
between the types.
You want to download the kernel source, so you leave the file transfer
type at binary. The binary type is also what you would use for any
non-text files -- such as graphic images, zip/gzip archives,
executable programs, etc. If in doubt, use binary mode.
3.4. Navigating and listing directories
You do an ls to see a list of the files. The ls command on ftp servers
is executed on the remote server, so the command line options that you
can use with it vary from server to server. The most common options
are generally available, check the manpage for ls for details.
ftp> ls
200 PORT command successful.
150 Opening ASCII mode data connection for /bin/ls.
total 33590
-r--r--r-- 1 root other 34348506 Dec 03 03:53 IAFA-LISTINGS
lrwxrwxrwx 1 root other 7 Jul 15 1997 README -> WELCOME
-rw-r--r-- 1 root other 890 Nov 15 13:11 WELCOME
dr-xr-xr-x 2 root other 512 Jul 15 1997 bin
dr-xr-xr-x 2 root other 512 Jul 15 1997 dev
dr-xr-xr-x 2 root other 512 Jul 18 1997 etc
drwxrwxrwx 11 ftp 20 4608 Nov 28 16:00 incoming
lrwxrwxrwx 1 root other 13 Jun 04 1998 ls-lR -> IAFA-LISTINGS
dr-xr-xr-x 17 root root 512 Jun 08 11:43 pub
dr-xr-xr-x 3 root other 512 Jul 15 1997 unc
dr-xr-xr-x 5 root other 512 Jul 15 1997 usr
226 Transfer complete.
If the ls command lists so many files that they scroll off the top of
the screen, you can use Shift-PageUp to scroll up. This works in Linux
console mode as well as in xterm or rxvt.
On public FTP archives, the downloadable resources are usually held in
the /pub directory. In this example, you already know that the kernel
sources are in the directory /pub/Linux/kernel, so you type the
following to get into that directory:
ftp> cd pub/Linux/kernel
250-README for kernel
250-
250-What you'll find here: kernel sources and patches
250-
250-
250 CWD command successful.
The messages you see, which begin with "250", are information messages
sent by the server. In this case, the ftp server is configured to
automatically send you the README file when you cd into the directory.
3.5. Downloading and uploading files
Now, after doing another ls, you see that you want to cd into the v2.2
directory. You do yet another ls, and find the file you want to
download. It is linux-2.2.13.tar.gz. So you type this:
ftp> get linux-2.2.13.tar.gz
local: linux-2.2.13.tar.gz remote: linux-2.2.13.tar.gz
200 PORT command successful.
150 Opening BINARY mode data connection for linux-2.2.13.tar.gz (15079540
bytes).
The ftp program has started saving the remote file linux-2.2.13.tar.gz
as the local file linux-2.2.13.tar.gz.
If you wanted to save it as the local file foo.tar.gz, you could have
specified it like this:
ftp> get linux-2.2.13.tar.gz foo.tar.gz
local: foo.tar.gz remote: linux-2.2.13.tar.gz
200 PORT command successful.
150 Opening BINARY mode data connection for linux-2.2.13.tar.gz (15079540
bytes).
If you want to download more than one file at a time, you'll have to
use the mget (multiple get) command. You can use mget together with a
space-delimited list of filenames you want to download, or you can use
wildcards with the mget command. For example:
ftp> mget linux*
Would get all files starting with the string "linux". Normally, mget
will prompt you for each file before it downloads it. You can toggle
this by using the prompt command.
Now let's say you've written a piece of software, and you want to
upload it to MetaLab to be included in their Linux software archive.
First, you'd change to the /incoming directory (most public FTP
servers have a directory, usually called incoming or uploads, where
files can be uploaded), then you'd use the put command:
ftp> cd /incoming
ftp> put foo.tar.gz
local: foo.tar.gz remote: foo.tar.gz
200 PORT command successful.
150 Opening BINARY mode data connection for foo.tar.gz.
226 Transfer complete.
10257 bytes sent in 0.00316 secs (3.2e+03 Kbytes/sec)
The put command works the same way as the get command, so you can use
mput to upload multiple files at the same time. You can also upload a
local file with a different filename on the server by specifying the
remote filename and/or pathname as an argument.
What if the file foo.tar.gz is not in your current local directory
when you try to upload it? You can switch local directories by using
the lcd (local change directory) command:
ftp> lcd /home/foo/
Local directory now /home/foo
3.6. Running shell commands
The ftp client supports using the bang (!) to run local commands. For
example, to get a listing of files in your current local directory, do
this:
ftp> !ls
The way this works is that ftp calls the shell (specified in the
$SHELL environment variable), and it is the shell which runs ls. Thus,
you can run any command-line which works with your shell simply by
prepending "!" to it (the default shell in most Linux distributions is
bash, the Bourne Again SHell). Please note that !cd does not work as
you would expect, this is why the lcd command exists.
3.7. Hash marks and tick
Wouldn't it be nice if you could watch the progress while you're
downloading a file with ftp? You can use the hash command to print out
hash marks as you download a file:
ftp> hash
Hash mark printing on (1024 bytes/hash mark).
As you can tell, ftp will print a hash mark for every 1024 bytes of
data you download.
There is also a tick option.
ftp> tick
Tick counter printing on (10240 bytes/tick increment).
This will print something to this effect as you download a file:
Bytes transferred: 11680
3.8. Other ftp commands
There are many other ftp commands. If you have the permissions to do
so (which you should, if you are connected to your own private shell
account), you can make a directory on the remote server using the
mkdir command. You can remove a file on the remote server using the
delete command, or rmdir to remove a directory. You can also change
file permissions using the chmod command.
For more elaborate information on using ftp, please see the online
help in the ftp program (accessible by typing help with no arguments
for a list of commands, or help <commandname> for specific help on a
command). You can also read the Unix man page for ftp by typing man
ftp at your command prompt.
4. Console FTP clients
The original ftp program was the original ftp client, and it is a good
investment to learn it. It's the only ftp client that you can be
certain is available on most systems (even Win32 comes with the ftp
command, albeit an archaic, braindead version of it).
There are many other console-mode (text-only) ftp clients available.
The listing here is by no means comprehensive, but includes the most
popular ones. Search at FreshMeat to find more.
4.1. NcFTP
NcFTP is the all-time favorite ftp client of many Unix users. It comes
bundled with most Linux distributions, and offers many advanced
features such as tab completion and bookmarks. Version 2 of NcFTP had
a curses based full-screen mode. This was done away with in Version 3
(now in beta).
It's not 100% compatible with the commands that standard ftp uses. For
example, get and put in NcFTP act like mget and mput do in standard
ftp. So if you want to save a remote file as a different local
filename, you'd have to do get -z remotename localname. Thankfully,
NcFTP has a nice online help system to assist you in learning the
commands.
You can get the latest version of NcFTP at .
4.2. lukemftp
A port of the NetBSD FTP client to other systems, lukemftp derives its
name from the author of most of the enhanced features, which include:
command-line editing, command-line fetches of FTP and HTTP URLs
(including via proxies), context-sensitive word completion, dynamic
progress bar, IPv6 support, modification time preservation, paging of
local and remote files, passive mode support (with fallback to active
mode), SOCKS support, TIS FWTK gate-ftp server support, and transfer
rate throttling.
I highly recommend lukemftp to users who don't want to change to
anything drastically different from the standard ftp client, but want
more advanced features.
You can get the latest version of lukemftp at .
4.3. lftp
lftp is a sophisticated command line based FTP client. Like bash, it
has job control. It uses the GNU readline library for input, so you
have command line completion and editing. lftp also has bookmarks,
mirroring support, and can transfer several files in parellel.
You can get the latest version of lftp at .
Debian packages are available at .
4.4. cftp
Comfortable FTP (cftp) is a full screen mode client. What it lacks in
features, it makes up for in ease of use. You browse through the
directories using the arrow keys and enter.
You should be able to get the latest version of cftp at .
4.5. yafc
Yafc is a very nice ftp client, with features including directory
cache, remote filename completion, aliases, colorized ls, recursive
get/put/ls/rm, nohup mode transfers, tagging (queueing), multiple
connections, proxy support and more. It has support for Kerberos4
authentication.
You can get the latest version of yafc from .
Debian packages are available at .
Redhat packages are available at .
5. X Window FTP clients
There are several graphical FTP clients designed to run on the X
Window system. These clients offer ease of use for users who are used
to graphical environments, and sometimes offer versatile options that
would be hard to implement in a text-based ftp client.
5.1. gFTP
gFTP is an FTP client for X Windows written using Gtk. The interface
has some similarities to the popular WS_FTP software commonly used on
a certain unstable operating system.
gFTP features simultaneous downloads, resuming of interrupted file
transfers, file transfer queues, downloading of entire directories,
ftp proxy support, remote directory caching, passive and non-passive
file transfers, drag-n-drop support, a very nice connection manager
and more.
If you are running Red Hat Linux and have the GNOME desktop installed,
then you probably already have gFTP. If not, you can download gFTP
from its homepage at .
5.2. WXftp
WXftp is an FTP client for the X Window System designed to be used
mainly on Linux workstations. It is written using the WXWindows
toolkit, so it can be compiled to use either Motif or GTK+
It includes an intuitive user interface (much like WS_FTP), a session
manager, on-line help, a progress bar, and more
Check out WXftp's homepage at .
5.3. LLNL XDIR and XFTP
LLNL XFTP was one of the first graphical FTP clients for Linux. It
supports FXP (file transfer between two remote hosts), and has a Motif
based interface.
More information is available at .
5.4. guiftp
Guiftp is a simple ftp client written with the GTK+ toolkit. It's good
if you don't need many features and want a simple, clean look.
Guiftp's homepage is at .
6. FTP Servers
6.1. How an FTP Server works
A traditional FTP server is executed from inetd (the internet
superserver daemon). The standard FTP port is port 21. When a user
tries to log in, the FTP server uses a standard system call to check
the user name and password against the entries in the system password
file, or the NIS tables if you are using NIS. If the login is correct,
the user is given access to the system.
Anonymous FTP works differently. The user logs in with either the
anonymous or the ftp username (this can be defined in the config
file). He is then given access to a directory tree that has been
chroot()'ed. This ensures that the user can not gain access to
directory trees he is not authorized for. The chrooted directory tree
usually contains a mock filesystem, with bin/, etc/, and lib/
directories. The files for download are usually put in the pub/
directory.
The reason for a mock filesystem in an anonymous FTP tree is that the
FTP daemon runs external commands for ls requests. You can also place
additional programs in the bin directory, and a user can run them with
the SITE command in his ftp client. For example, Red Hat's FTP
includes the RPM command (for users to query RPM packages on the
site).
Some FTP servers work differently. For example, some will allow user
accounts to be set up independant of the system-wide password file
(FTP-only accounts). Some servers (ProFTPD and NcFTPd for instance)
have built-in ls commands and do not need a special directory tree
within the chroot structure. Other ftp servers stray altogether from
the standard ftp concept. FTP4ALL, for example, does not use system
passwords at all. It uses it's own user and group file, and has
features such as upload/download ratio and customizable server
messages.
6.2. Help with FTP Servers
6.2.1. WU-FTPD
WU-FTPD is the ftp daemon included with many Linux distributions,
including Red Hat and Caldera. You can learn more about WU-FTPD at .
The WU-FTPD FAQ can be found on the web at .
6.2.2. ProFTPD
ProFTPD is a powerful FTP server that includes Apache-style
configuration, extensive support for virtual hosts, and internal ls.
A complete command reference and downloads can be found at
