A long time ago, working for a BBS, I wrote a nice interactive utility to review and change user configurations. I named it uc ("user configure"). After some te

A long time ago, working for a BBS, I wrote a nice interactive utility to review and change user configurations. I named it uc ("user configure"). After some testing, I installed it in /usr/local/bin. Time to use it! # uc /bbs/users/* Nothing happens. It needs some time to read all users' configuration files before displaying the user interface, but it's taking too long. What's happening? I decide to interrupt it. Shortly after, we find out all user accounts starting with A, B, and C are wiped out. Apparently, unbeknown to me, somebody had previously written a utility to delete user accounts. It was named uc (user clear), and was installed in /usr/bin. Fortunately we had fairly recent backups. That day I learned about hash -r.