'''[http://en.wikipedia.org/wiki/Secure_Shell%|%ssh]''', short for '''secure
shell''',  provides a secure shell on a remote system.



** See Also **

   [http://www.openssh.org/%|%openssh]:   An open implementation of the secure protocol for working with remote shells.

   [http://www.ssh.com/%|%ssh.com]:   Another site at least associated with source code base for SSH implementations.

   [https://web.archive.org/web/20031130230229/http://www.phaseit.net/claird/comp.security.ssh/ssh.html%|%Cameron Laird's personal notes on ssh]:   

   [Automating sftp with Tcl]:   

   [TLS]:   

   [http://geekpit.blogspot.com/2006/04/five-minutes-to-more-secure-ssh.html%|%Five Minutes to a More Secure SSH]:   

   [http://groups.google.com/groups?oi=djq&selm=an_408378721%|%ssh and Tcl sockets], 1998-11-03:   Includes an example that uses Tcl together with ssh.

   [multixterm]:   

   [http://themediahost.de/secpanel/%|%SecPanel]:   Serves as a GUI for managing and running SSH (Secure Shell) and SCP (Secure Copy) connections. 

[https://web.archive.org/web/20200514012746/http://themediahost.de/secpanel/images/ssh.png]




** Description **

The security infrastructure of SSH is completely separate from that of [SSL].

   '''SSH''' — Secure (Remote) Shell:   Typically used to connect securely to a machine where you have an account. At heart, it is a "secure [telnet]" which however can carry lots of other traffic (forwarded IP ports, file transfers) within the encrypted connection.
   '''SSL''' — Secure Sockets Layer:   Provides a secure connection without requesting login, but the ''server'' is typically expected to authenticate its identity.



** ssh with sudo **

This isn't directly related to Tcl, but I didn't see a simple answer
anywhere else, so here is a an example of sh command to connect to a
remote system, and execute a command on that system as another user,
without exposing the password.  In this example, the task is to back up
the entire filesystem starting at root:

======none
(
        printf 'Enter sudo password: ' >&2
        stty -echo; read; stty echo
        exec 3<<<"$REPLY"
        rsync -ACHXavzPie 'bash -c '\''{ cat <&3; cat -; } \
        | ssh "$@" &'\'' fakearg0forsh ' --rsync-path "sudo -S rsync" \
                        --backup-dir=/path/to/backupchanged --fake-super \
                        --exclude=/dev/ --exclude=/mnt/ --exclude=/proc \
                        --exclude=/tmp/ --exclude=/sys \
                        <username>@<host>:/ /path/to/backupdir/
)
======




** Discussion **

Anyone know of a Tcl extension binding to one of the ssh libraries?

Perhaps [D. J. Hagberg]'s example of port forwarding, from 1998 [http://groups.google.com/groups?oi=djq&selm=an_408378721] is useful.

[CMcC] I've thrown together some code to allow [remote ssh tcl] execution.

[hkoba]: You can also use [comm via ssh] to send/eval any script to remote host.

[AMG]: I whipped up a Tcl script that allows you to [ssh] to multiple hosts at the same time, using a single command and a single set of ''stdin/stdout/stderr.''  Try running [bash] with it, heh heh.  (It really works!)  For details, see [multissh].

[Justis]: The [TclCURL] library seems to have some SSH features compiled into it: [http://personal1.iddeo.es/andresgarci/tclcurl/english/docs.html]

----
Russell Treleaven reports
[http://groups.google.com/groups?q=Russell+Treleaven+Expect&hl=en&lr=&ie=UTF-8&c2coff=1&selm=GrVTc.1017%24FZs1.32%40news04.bloor.is.net.cable.rogers.com&rnum=2]
that he successfully automates ssh client sessions on a [Windows]
host with [ActiveState]'s [Expect]
and the ssh2 executable
[http://www.ssh.org/].
He uses the "send slow" option.
Both of these applications are proprietary.

----

[TV]: I've within some limitations, used the [cygwin] ssh facility, which is quite extensive,
except varying from a drag to requiring out of package documentation to install. It is almost
[unix], though. It also contains working executables to use openSSL to create and deal with
[certificates], I  used it successfully to make a secure httpd tick, except I forgot how.


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