(now we are getting networked apps, be careful to try and test on a
securely isolated system!)

These programs grant no privileges, but they give an idea of how well
the modules are working.

blank is new as of Linux-PAM-0.21. If you are writing/modifying an
application it might be a place to start...

xsh is new as of Linux-PAM-0.31, it is identical to blank, but invokes
/bin/sh if the user is authenticated.