Dean Wilson@UnixDaemon: ... be good, get good or give up.
http://blog.unixdaemon.net/cgi-bin/blosxom.pl/geekstuff/twitter_and_bash_bad_ideas.html
"To make it 'useful' you'll need to run the following in your bash shell: PROMPT_COMMAND='history | tail -n 1 | /path/to/twitter_post.pl' and tada! People really will know what you're doing RIGHT NOW. Ahem, sorry."