CalDAV command line client?

The CalDAV wiki has a list of clients, only one of which seems to be a command line tool: cadaver.

More recently, a CalDav capable command line client called khal has appeared to fill this gap. I have been using it and integrating it with Mutt and it is working nicely. With some simple scripts, I can view calendar information in Mutt and then import it to khal where it is then synched to my CalDav server and propagated to my other machines or devices.

It is still described as in "the early stages of development", but I have found it to be stable and simple to use.

The next step, according to the developer, is to use vdirsyncer as the backend for synching: it is set up much like OfflineIMAP, with Remote and Local data stores: synching between the two. Currently there is a vdir branch to test this functionality.

Calcurse does support CalDAV (still experimental) in the latest release. It's packaged for the most common GNU/Linux Distributions and BSDs.