PyTwerp is a command line client for Twitter and Identi.ca. Since the last changes in the Twitter authentication system, and the similar movement by Identi.ca to mimic the Twitter API, PyTwerp stopped working with Twitter.
Fortunately, I have submitted a patch that makes it work back with both Twitter and Identi.ca. The patch has not yet been merged in the main branch, but I hope it will be merged soon.
If you want to tweet from your command line, have a look a PyTwerp.