I couldn't find a good CRC32 checksum utility that properly handled wildcards, so I wrote my own.
I actually first wrote this a very long time ago using DJGPP. Actually, thinking about it it might have been the first 32-bit program I ever wrote. That compiler made it very easy because the command-line handling did the directory recursion for me (though it did mean you had to use the awkward syntax "crc32 ...\*" instead of "crc32 *" or "crc32 .". However, 64-bit Windows won't run DOS programs so it needed a rewrite, and once I had completed the filesystem routines I mentioned before it was just as easy.
This program is very handy for comparing contents of large directories across machines ("windiff -T" would copy everything across the network so would take forever.) Just run it on the two directories locally and compare the output.
I used to use this for weekly backups of my machine. It's nice to see exactly what's changed since the last backup so I can delete the backup files made by my text editor and anything else I didn't really mean to keep. Nowadays I use rsync to a Linux machine which amounts to something very similar but more automatically.
[...] crc32 - a handy utility for computing CRC32 checksums of files. [...]