Comment by eqvinox

Something like:

    OnCalendar=00/6

You can test it with:

    systemd-analyze calendar --iterations=6 '0/6:00:00'

The format is `DayOfWeek Year-Month-Day Hour:Minute:Second`

https://www.freedesktop.org/software/systemd/man/latest/syst...

  $ systemctl cat public-inbox-watch@.timer
  # /etc/systemd/system/public-inbox-watch@.timer
  [Unit]
  Description=Periodic fetch of public mailing list

  [Timer]
  # twice a day
  OnCalendar=*-*-* 5,17:35
  RandomizedDelaySec=1h
  Persistent=true

  [Install]
  WantedBy=multi-user.target