I was trying to find out if we’ve got any kind of squid reporting installed on our proxy server. Just going though the /etc folder didn’t cut it, so I did:
aptitude search squid
aptitude search sarg
Check the left of the screen, if it is displaying an i next to the listed item then it means it is installed. Hope it helps! 🙂
If you’ve got better ways to search for installed items please feel free to comment.