[ale] Scriptable motd for initial SSH login?

[Geoffrey Myers]

Wolf Halton wrote:
> #!/bin/bash
> echo -n "Welcome to the Computer $USER"
> 
> Unless there is absolutely going to only ever be one user you want to so 
> treat, I would write a script for it.

If you just want it to display for that particular user, you can code 
that as well.

if [ $USER = "user"] ...

> 
> On Wed, Sep 14, 2011 at 3:37 PM, James Sumners <james.sumners at gmail.com 
> <mailto:james.sumners at gmail.com>> wrote:
> 
>     Well, I had thought of that, but then I read [1] and it says:
> 
>     "SSHRC
> 
>         If the file ~/.ssh/rc exists, sh(1) runs it after reading the
>     environment
>         files but before starting the user's shell or command.  It must
>     not pro-
>         duce any output on stdout; stderr must be used instead."
> 
>     This is explicitly counter to what I want to do so I didn't even
>     bother trying it. But, since you guys have suggested it, I just tried
>     adding the following to ~/.ssh/rc and logging in:
> 
>     #!/bin/bash
>     echo -n "Does this work?\n"
> 
>     Guess what? It worked. So, thank you for making me re-examine this
>     option.
> 
>     [1] -- http://www.manpagez.com/man/8/sshd/
> 
>     On Wed, Sep 14, 2011 at 15:02, Chris Fowler
>     <cfowler at outpostsentinel.com <mailto:cfowler at outpostsentinel.com>>
>     wrote:
>      > On Wed, 2011-09-14 at 14:31 -0400, Michael H. Warfield wrote:
>      >
>      >> Anything wrong with sticking it in their (or the default) sshrc
>     file?
>      >>
>      >
>      > I think that is an excellent solution.
>      >
>      >
>     --------------------------------------------------------------------------------
>      > 5.6.4. Arbitrary Actions with /etc/sshrc
>      > When a user logs in, the normal Unix login system typically runs some
>      > shell scripts, such as /etc/profile. In addition, sshd runs the
>      > script /etc/sshrc for each SSH-based login. This feature lets the
>     system
>      > administrator run special commands for SSH logins that don't
>     occur for
>      > ordinary logins. For example, you can do some additional logging
>     of SSH
>      > connections, print welcome messages for SSH users only, and set
>      > SSH-related environment variables.
>      >
>      > In all three, SSH1, SSH2, and OpenSSH, /etc/sshrc is processed by
>      > theBourne shell ( /bin/sh) specifically, rather than the user's
>     shell,
>      > so that it can run reliably for all accounts regardless of their
>     various
>      > shells. It is run for logins (e.g., ssh my-host) and remote commands
>      > (ssh my-host /bin/who), just before the user's shell or command is
>      > invoked. It runs under the target account's uid, so it can't take
>      > privileged actions. If the script exits due to an error (say, a
>     syntax
>      > error), the SSH session continues normally.
>      >
>      > Note that this file is run as input to the Bourne shell: sshd
>      > runs /bin/sh /etc/sshrc, not /bin/sh -c /etc/sshrc. This means
>     that it
>      > can't be an arbitrary program; it must be a file containing
>     Bourne-shell
>      > commands (and it doesn't need the execute mode bit set).
>      >
>      > /etc/sshrc operates machinewide: it is run for every incoming SSH
>      > connection. For more fine-grained control, each user may create the
>      > script ~/.ssh/rc to be run instead of /etc/sshrc. [Section 8.4, "The
>      > User rc File "] /etc/sshrc isn't executed if ~/.ssh/rc exists in the
>      > target account. Note that SSH rc files interact with X
>     authentication.
>      > [Section 9.3.5.2, "xauth and the SSH rc files"]
>      >
>      >
>     --------------------------------------------------------------------------------
>      >
>      > Create an /etc/sshrc and then create individual files
>      > in /etc/user_motds/  Then use the UID's to display the individual
>     files.
>      > Something as simple as this:
>      >
>      > #!/bin/sh
>      >
>      > MOTD="/etc/user_motds/${UID}.txt
>      >
>      > if [ -f $MOTD ]
>      > then
>      >  cat $MOTD
>      > fi
> 
> 
> 
>     --
>     James Sumners
>     http://james.roomfullofmirrors.com/
> 
>     "All governments suffer a recurring problem: Power attracts
>     pathological personalities. It is not that power corrupts but that it
>     is magnetic to the corruptible. Such people have a tendency to become
>     drunk on violence, a condition to which they are quickly addicted."
> 
>     Missionaria Protectiva, Text QIV (decto)
>     CH:D 59
> 
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> 
> 
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-- 
Until later, Geoffrey

"I predict future happiness for America if they can prevent
the government from wasting the labors of the people under
the pretense of taking care of them."
- Thomas Jefferson