When I started looking for a terminal calendar application the primary result was calcurse. Calcurse has also an integrated todo list, which I in my particular case don't need, because I got todo.txt for that. But uses it's own plaintext for storing it's appointments. Which is problematic for me when I want to use my existing calendar from Nextcloud. Calcurse has experimental caldav support, but the import and export scripts did not work properly for me and just messed my calendar up by creating broken calendar cards and doubling all my events each sync.

Khal is my solution. It is similar to khard, a terminal vcard contact book. Both applications work perfectly with vdirsyncer together. The only packages required are vdirsyncer and khal. Ond Arch linux they can pe installed using pacman.

sudo pacman -S vdirsyncer khal

Otherwise i'd recommend pip.

pip install vdirsyncer khal

Synchronize with nextcloud

First of all I add the vdirsyncer synchronisation.

~/.config/vdirsyncer/config

[pair calendar]
a = "calendar_local"
b = "calendar_remote"
collections = ["from a", "from b"]
metadata = ["displayname"]

[storage calendar_local]
type = "filesystem"
path = "~/.calendar"
fileext = ".ics"

[storage calendar_remote]
type = "caldav"
#Can be obtained from nextcloud
url = "https://yournextcloud.example.lcl/remote.php/dav/calendars/USERNAME/personal/"
username = "<USERNAME>"
#Instead of inserting my plaintext password I fetch it using pass
password.fetch = ["command", "pass", "nextcloud"]
#SSL certificate fingerprint
verify_fingerprint = "FINGERPRINT"
#Verify ssl certificate. Set to false if it is self signed and not installed on local machine
verify = true

The SSL certificate fingerprint can be obtained by the following line

echo -n | openssl s_client -connect your.calserver.lcl:443 | openssl x509 -noout -fingerprint

Now we can run vdirsyncer discover to create the necessary directories to then synchronize with vdirsyncer sync. I recommend to setup a cronjob for vdirsyncer sync to stay synchronized.

Configure khal

The thing left to do is to tell khal where our calendar is and some other things to display.

~/.config/khal/config

[calendars]
    #Can contain as many calendars as we want
    [[personal]]
    path = ~/.calendar/CALENDARNAME
    type = calendar
    priority = 2
    color = dark green

[default]
#Set calendar used for new events when no one is given
default_calendar = personal
#Color dates when containing an event
highlight_event_days = true
#Timespan of days whose events are shown in e.g. list
timedelta = 7d

#Set printing of dates
[locale]
timeformat = %H:%M
dateformat = %m/%d/%Y
longdateformat = %m/%d/%Y
datetimeformat = %m/%d/%Y %H:%M
longdatetimeformat = %m/%d/%Y %H:%M

ikhal (interactive khal) gives us then this nice prompt. It is shipped with khal and khal interactive has the same effect

Keybindings for khal