Emacs Tip #2: global-auto-revert-mode

If you often look at files that are updated (perhaps a log file for a
running process), or perhaps ClearCase files (that change when you
update the config spec), you'll want to make sure you're looking at
the most recent version of the file.

To do this, add the following to your .emacs:

(global-auto-revert-mode 1)

For more documentation type:

C-h f global-auto-revert-mode RET