glyph pointed me at sloccount, after I mentioned how big the wc -l `find -name *.py` was for MoinMoin. Apparently it has some silly md5sum dependency. OS X does not come with md5sum, but it does have an md5 tool with different output. Here's a quickie shell script:
#!/bin/sh
/sbin/md5 $@ | sed 's#MD5 (\(.*\)) = \(.*\)#\2 \1#'
sab39: I don't think there is a cross-platform graphical diff tool, however for Windows I believe WinCvs comes with one, and for OS X there is File Merge (part of the Developers Toolkit).