Samhain rocks da house!!!
This is bar none *THE* coolest integrity checker out there. I've played with every single one I can find: Tripwire, Sentinel, Aide, FCheck, Viper, etc., etc., and this is the sh*t!
1. Platform-independent (builds on just about anything)
2. Small footprint
4. Stealth mode (very cool)
5. Clean code (not somebody's sophomore C project)
6. Client / server mode (send reports to a central server over a secure channel)
7. Obscure Glen Danzig reference
8. Docs that don't suck and an active development community
An open, cross-platform journaling program.
A scientific plotting package.