(Last updated Wed Sep 24 00:44:43 EDT 2003)
|sourceforge project summary||http://sourceforge.net/project/?group_id=7487|
Descriptionzssh (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 ( currently ^@ ), 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 file transfer mode. ^D may also be used for this purpose.|
|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.
|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 :
|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.
Do not ask user any question -h
the secure shell (local machine) -s cmd
run cmd as remote shell instead of the default "ssh -e none" (zssh) or "telnet -8 -E" (ztelnet)
ex: zssh -s "rsh -x"
zmodem send and receive programs. Should be both on local and remote machine, and (hopefully) of compatible versions. -z ^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.
EnvironmentSetting 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.
Requirementsthe 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.|
- If file transfer is initiated but never completes
( ie a line like :
Bytes Sent: 38144/4610624 BPS:3424 ETA 22:15
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 to stop it
- Use `sz -y <files>' to overwrite files on the other side
- man sz !
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 =)
JB for telling me about sourceforge.
The sourceforge team.
|(C) 2001 Matthieu Lucotte|