Is there a CLI utility that allows one to sync up with their iCloud calendar (i.e., iPhone calendar on the cloud) to modify calendar events, etc.?
It now [...] works with iCloud. However, syncing with iCloud ran into a server bug (reported as 17001498 "CalDAV REPORT drops calendar data") and needs further work.
Another solution is suggested in this blog:
I used a software from http://icloud.niftyside.com/ which I installed on my Uberspace. It was just unpacking it into a directory of the webserver and visiting the site. Then entering my credentials and I got all the URLs.