Running a console application on connection

Question

I hope this is the right forum for this, and excuse the naive question.

I would like to provide an "guest" login to a (non-dedicated) linux server and run just one console application. The user cannot do anything more than use this application. A scenario could be:

 ssh dervinATsomehost.com (no pasword)

and the just automatically execute the shell app, say

  Welcome to Dervin's shell.
  Dervin$

when the user says exit, the whole connection would drop, not just the application.

This seems relatively simple, but I wouldn't know where to start.

Thanks.

Answer 1

Just set the user's shell to the application by changing "/bin/sh" (or "/bin/bash") in the /etc/passwd file to whatever program you'd like them to run. Be aware that many programs will allow the user to start a shell, though.

Answer 2

Depending on what you'd like them to do; you can also install something like rssh (http://www.pizzashack.org/rssh/).