Khal is a standards based CLI (console) calendar program. CalDAV
compatibiliy is achieved by using vdir/vdirsyncer as a backend,
allowing syncing of calendars with a variety of other programs on
a host of different platforms.

khal is currently in an early stage of development, has a limited
feature set and is probably full of bugs. If you do try it out,
please make sure you have a backup of your date and please report
back any bugs you might encounter.