I constantly need to diff two directories just to check what files have changed between revisions.
When you do a CVS checkout of two separate branches whether they’re incremental or not, sometimes you need to check which files differ as a pre-check before doing something else. Here’s a little code snipped that will allow you to do just that:
diff -rbB --brief $1 $2 | egrep -v '(CVS|.svn|~|\.#)'
Throw that in a file named ‘diffdir’ or whatever you like in your ~/bin directory, make it executable and you’re good to go.