** lftp-2.4

This package `lftp' contains the following components:

   lftp
      sophisticated command line file transfer program (ftp/http client).

   lftpget
      shell script for downloading by URL, calls `lftp -c'.

lftp is written in C++ and uses a cooperative-threaded model.


lftp
~~~~
lftp is command line file transfer program. It supports FTP and HTTP
protocols. GNU Readline library is used for input.

Low level stuff supported: ftp proxy, http proxy, ftp over http,
opie/skey, fxp transfers, automatic retrying on non-fatal errors and
timeouts, ipv6, socks. See FEATURES for more detailed list of
features.

Every operation in lftp is reliable, that is any non-fatal error is
ignored and the operation is retried. So if downloading breaks, it
will be restarted from the point automatically. Even if ftp server
does not support REST command, lftp will try to retrieve the file from
the very beginning until the file is transferred completely.

lftp has shell-like command syntax allowing you to launch several
commands in parallel in background (&). It is also possible to group
commands within () and execute them in background. All background jobs
are executed in the same single process. You can bring a foreground
job to background with ^Z (c-z) and back with command `wait' (or `fg' which
is alias to `wait'). To list running jobs, use command `jobs'. Some
commands allow redirecting their output (cat, ls, ...) to file or via
pipe to external command. Commands can be executed conditionally based
on termination status of previous command (&&, ||).

If you exit lftp when some jobs are not finished yet, lftp will move
itself to nohup mode in background. The same happens when you have a
real modem hangup or when you close an xterm.

lftp has builtin mirror which can download or update a whole directory
tree. There is also reverse mirror (mirror -R) which uploads or
updates a directory tree on server.

There is command `at' to launch a job at specified time in current
context, command `queue' to queue commands for sequential execution
for current server, and much more.

On startup, lftp executes /etc/lftp.conf and then ~/.lftprc and
~/.lftp/rc. You can place aliases and `set' commands there. Some
people prefer to see full protocol debug, use `debug' to turn the
debug on. Use `debug 3' to see only greeting messages and error
messages.

lftp has a number of settable variables. You can use `set -a' to see
all variables and their values or `set -d' to see list of defaults.
Variable names can be abbreviated and prefix can be omitted unless the
rest becomes ambiguous.

Use command `help' or read documentation (man lftp) to learn more.

If lftp was compiled with ssl support, then it includes software
developed by the OpenSSL Project for use in the OpenSSL Toolkit.
(http://www.openssl.org/)

Where to get
~~~~~~~~~~~~
By FTP:
	ftp://ftp.yars.free.net/pub/software/unix/net/ftp/client/lftp/
	ftp://metalab.unc.edu/pub/Linux/system/network/file-transfer/
By HTTP:
	http://ftp.yars.free.net/pub/software/unix/net/ftp/client/lftp/
	http://metalab.unc.edu/pub/Linux/system/network/file-transfer/
By CVS:
	CVSROOT=:pserver:anonymous@swing.yars.free.net:/home/lav/cvsroot
	export CVSROOT
	cvs login (empty password, just hit enter)
	cvs -z9 co -r lftp-2-0-3 lftp (if you omit -r option, you'll get
		latest development sources)

See also home page `http://lftp.yar.ru/'.

Internals
~~~~~~~~~
All this is based on SMTask class which implements non-preemptive
multitasking via Do method. The method Do does a little bit of work,
sets wake up condition (block member) and returns.

The class Ftp allows reliable deliver of files via ftp protocol, it hides
all the details from application and allows asynchronous operation.
Reconnect and reget are done as necessary. It can also speed up ftp
operations by sending several commands at once and then checking all the
responses. It seems this sometimes does not work, so it is disabled by
default. To turn it on, use `set sync-mode n' in lftp or --async-mode for
ftpget.

Note that sending several commands is considered as violation or
protocol, but RFC959 says: ``The user-process sending another command
before the completion reply would be in violation of protocol; but
server-FTP processes should queue any commands that arrive while a
preceding command is in progress.''

It is known that some network software dealing with address
translation works incorrectly in case of several FTP commands in one
network packet.


Systems
~~~~~~~
The package is known to compile on Solaris2.5(gcc), Linux, FreeBSD,
SCO v5.0(gcc), IRIX(gcc), Tru64(gcc) and other systems. If you can't
compile it on your system, let me know. It is possible that lftp
version 2.0 can be compiled with non-gcc compilers since it does not
have gcc-isms, and it was successfully compiled by Sun C++ v5.0
compiler using CXXFLAGS="-compat=4 -features=bool".


Mailing list
~~~~~~~~~~~~
There is a mailing list for discussion of lftp and announcements. It
is managed by majordomo; to subscribe, send mail to
majordomo@uniyar.ac.ru with `subscribe lftp' in body of message; to
send letters to the list, send them to lftp@uniyar.ac.ru; to
unsubscribe, send mail to majordomo@uniyar.ac.ru with `unsubscribe
lftp' in body of message. This is low volume list.

There is also list lftp-devel@uniyar.ac.ru for snapshot announcements
and other development.

These lists are archived at
   http://www.mail-archive.com/lftp%40uniyar.ac.ru/
   http://www.mail-archive.com/lftp-devel%40uniyar.ac.ru/


Author
~~~~~~
Author: Alexander V. Lukyanov <lav@yars.free.net>
My home page: http://www.yars.free.net/~lav/

Comments and bug reports are welcome.
