NAME
zssh - interactive file transfer wrapper for ssh
SYNOPSIS
zssh [zssh options] [--] [ssh options]
ztelnet [zssh options] [--] [telnet options]
DESCRIPTION
zssh (Zmodem SSH) is a program for interactively transferring files to
a remote machine while using the secure shell ( ssh ). It is intended
to be a convenient alternative to scp , allowing to transfer files
without having to open another session and re-authenticate oneself.
zssh is an interactive wrapper for ssh used to switch the ssh
connection between the remote shell and file transfers. This is
achieved by using another tty/pty pair between the user and the local
ssh process to plug either the user’s tty (remote shell mode) or
another process (file transfer mode) on the ssh connection.
ztelnet behaves similarly to zssh, except telnet is used instead of
ssh. It is equivalent to ’zssh -s "telnet -8 -E"’
Files are transferred through the zmodem protocol, using the rz and sz
commands.
zssh behaves as an usual ssh session until the escape sequence is
depressed ( default is ^@ which can be produced by pressing C-space, or
C-2, or C-‘ ), which enables file transfer mode. A new prompt is then
displayed, and commands can be executed locally to initiate file
transfers (among other things). It roughly behaves as a local shell
featuring line edition, history and completion (thanks to libreadline),
globbing, and escape characters ( " ’ and \ ).
The following builtins are handled by zssh itself: ? , cd , disconnect
, escape , exit , help , hook , quit , repeat , rz , suspend , sz ,
version
cd <dir> change current directory
disconnect disconnect and exit
escape [^X] Change escape key to ^X. Without argument, print
current escape key
exit exit file transfer mode. ^D may also be used for
this purpose.
help print help and tips
?
hook prg [args] Hook program ’prg’ on the the pty. Its standard
input and output will go through the ssh channel.
typing ’sz’/’rz’ is in fact equivalent to ’hook
sz’/’hook rz’
A weird imagination is most useful to gain full
advantage of this feature.
quit same as exit.
repeat repeats cmd forever (^C to interrupt). Useful for
example if you use a remote script invoking "sz"
and you don’t want to be typing "rz" each time...
Remember however that several files can be
transferred by a single sz/rz pair so this is not
usually necessary to use repeat.
rz Receive files from the remote machine. runs rz and
plugs the process on the ssh connection. running
sz on the REMOTE machine is required :
1) run ‘sz <remote_file> ...’ from the remote
machine shell
2) press the escape sequence (C-space) to enter
file transfer mode
3) run the ‘rz’ builtin
suspend suspend zssh (back to the local machine shell)
sz <file> ... Send files to the remote machine. runs sz and plugs
the process on the ssh connection. There is no
need to manually run rz on the remote side.
version print version information
builtins rz , sz , hook and exit return to shell mode after completion.
OPTIONS
-f
--force Do not ask user any question
-h
--help show basic help
-s cmd
--shell cmd run cmd as remote shell instead of the default "ssh
-e none" (zssh) or "telnet -8 -E" (ztelnet)
ex: zssh -s "rsh -x"
-V
--version show version
-z ^X
--zssh-escape ^X set escape sequence to ^X
-- may be used to separate zssh options from ssh ones
Other arguments are passed verbatim to ssh/telnet/whatever.
ENVIRONMENT
ZSSHESCAPE
Setting the ZSSHESCAPE environment variable allows to
override the default escape sequence. ZSSHESCAPE should
contain only two characters of the form ‘^X’, meaning that ^X
is to be the new escape sequence.
REQUIREMENTS
the following binaries need to be properly installed for zssh to work :
ssh/telnet/...
the remote shell to be executed (local machine)
sz rz zmodem send and receive programs. Should be both on local and
remote machine, and (hopefully) of compatible versions.
TIPS
If file transfer is initiated but never completes
( ie a line like :
Bytes Sent: 38144/4610624 BPS:3424 ETA 22:15
or
Bytes Sent: 0/ 513 BPS:0 ETA 00:00 Retry 0: Got
ZCAN
can be seen, but transfer never completes
)
Chances are the pty/tty on one of the systems are not 8-bit clean.
(Linux is 8-bit clean, NetBSD is not).
Using the -e (escape) option of rz should solve this problem.
Transfers can be interrupted with ^C (somewhat experimental =)
If you get stuck in rz/sz (for example you’ve just ran rz, but you then
decided not to transmit anything), hit a dozen ^X (Ctrl-X, not the zssh
escape!) to stop it
Use ‘sz -y <files>’ to overwrite files on the other side
BUGS / LIMITATIONS
You may sometimes have to hit return 2 or 3 times after file transfer
completion in order get back to the shell. Some digits are usually
displayed; don’t worry it won’t harm (you or your term) ...
the tty may (sometimes) be somewhat upset after an interrupted transfer
( using ^C ). typing ‘reset’ in this case should help.
no pipe, redirection (and other stuff) support in shell ... but after
all there are already wonderful shells around =)
CREDITS
ttssh’s author - Robert O’Callahan - for the original idea
The sourceforge team.
AUTHOR
Matthieu Lucotte <gounter@users.sourceforge.net>
zssh homepage: http://zssh.sourceforge.net
SEE ALSO
ssh(1), telnet(1), scp(1), sz(1), rz(1), readline(3),