Last lecture on looking after Unix

- only keep things in files on the machine if you are going to need them
  again *in machine-readable form on merlin*.
  In most cases, printing out a copy and keeping that is the best solution.

- logging out gracefully (control-P d is a last-ditch emergency measure,
  and logging out with stopped jobs is not the way you want to do it
  (what does the OS do with them?  Kill them?  Set them running again?
  it can't know.)

- being sensible about machine loading.  If there are lots of people on,
  don't sit there confing people and playing games.