** lftp-4.5.x

This package `lftp' contains the following components:

   lftp

      sophisticated command line file transfer program (ftp/http client,

      also supports several other protocols).

   lftpget

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

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

lftp

~~~~

lftp is sophisticated file transfer program with command line interface. It

supports FTP, HTTP, FISH, SFTP and FILE (local FS) protocols. GNU Readline

library is used for input. BitTorrent protocol is supported as built-in

`torrent' command.

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, http/1.1, sftp v3-v6. 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. It is possible to attach to backgrounded

lftp instance using `attach' command in lftp, e.g. `lftp -c attach'.

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. It is also possible to synchronize two servers,

FXP is used automatically if possible.

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. if ~/.lftp directory does not

exist, XDG directories are used instead: ~/.config/lftp, ~/.local/share/lftp

and ~/.cache/lftp.

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.yar.ru/pub/source/lftp/

By HTTP:

	http://lftp.yar.ru/ftp/

By GIT (development):

	https://github.com/lavv17/lftp

See also the 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.

There are also some useful classes: Timer, TimeDate, *Buffer, xstring,

xarray, xlist, xmap, xheap, Ref etc. Timers are ordered using a heap data

structure. Primitive classes were implemented with performance and low

memory consumption in mind. Standard C++ library is not used, since lftp

development started when it was not so standard yet (and boost did not even

exist).

Access to remote files is performed via FileAccess class, which is base

class for all protocols. NetAccess is for network file access. There is

also LocalAccess for local files access. SSH_Access is for SSH based

protocols: FISH and SFTP.

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.

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 Solaris(gcc), Linux, FreeBSD, NetBSD,

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 mailman; to subscribe, send mail to lftp-subscribe@uniyar.ac.ru;

to send letters to the list, send them to lftp@uniyar.ac.ru; to

unsubscribe, send mail to lftp-unsubscribe@uniyar.ac.ru. This is a low

volume list. See also http://univ.uniyar.ac.ru/mailman/listinfo/lftp.

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/

You can also submit pull requests or issues to GitHub:

   https://github.com/lavv17/lftp

Author

~~~~~~

Author: Alexander V. Lukyanov <lav@yars.free.net>

My home page: http://lav.yar.ru/

My other E-Mails: lav@yar.ru, lav@netis.ru, lavv17f@gmail.com

Other people have contributed to lftp development, see the THANKS file.

Comments and bug reports are welcome. Please send them to the list:

<lftp@uniyar.ac.ru>. Subscribe if you want your messages to be sent to the

list quickly.

License

~~~~~~~

Copyright (c) 1996-2014 by Alexander V. Lukyanov (lav@yars.free.net)

LFTP is free software: you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation, either version 3 of the License, or

(at your option) any later version.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License

along with LFTP.  If not, see <http://www.gnu.org/licenses/>.