Shutting off accounts

[Larry Philps]

When I was managing hordes of undergraduate accounts at the University of
Toronto.  I used to change a users shell to restrict his login.  There was a
directory call "/bin/shells", and if I wanted to turf a user on January 1, I
would put an entry in /bin/shells called, for example, "deleteonJan1".  It
was a simple program that just printed the contents of a text file, dependent
on its name, slept for 5 seconds, then exited.

Thus a person logging in would see a message saying that the account was to
be purged, when it was to go, and who to complain to if that was a mistake.
If indeed it was a mistake, a simple chsh fixed things.

For that matter, I went crazy and gave students a shell whose name depended
on their graduating year.  For example, /bin/shells/csh8T9.  Then I could
have the exactly the same password file on all machines on the net, but
control access to the pool of machines by changing the machines on which
csh8T9 was a link to csh, as opposed to a link to a "niceTry" error program.