I would like to run a script every 30 minutes on my RbPi, **but not immediately after boot**. \
Example: If I boot my RbPi at 15:15, the script should run at 15:30 not before.\
Setup: My RbPi has **no internet connection** to sync its time, it relies on an **external RTC**. To sync the time I followed [this post][1].


What I did so far:\
I have the following two files, generated using\
`sudo systemctl edit --force --full test.service` and\
`sudo systemctl edit --force --full test.timer`

```
# test.service
[Unit]
Description=test

[Service]
Type=simple
ExecStart=echo "TEST"

# test.timer
[Unit]
Description=test

[Timer]
OnCalendar=*:0/30
Persistent=false

[Install]
WantedBy=default.target
```

Unfortunately this dummy script runs immediately during the boot sequence as shown by `journalctl -r`:
```
...

Oct 21 14:11:43 rbpi0 kernel: Bluetooth: BNEP (Ethernet Emulation) ver 1.3
Oct 21 14:11:43 rbpi0 systemd[1]: Finished Online ext4 Metadata Check for All Filesystems.
Oct 21 14:11:43 rbpi0 systemd[1]: e2scrub_all.service: Succeeded.
Oct 21 14:11:43 rbpi0 systemd[1]: Starting Daily man-db regeneration...
Oct 21 14:11:43 rbpi0 systemd-udevd[128]: Using default interface naming scheme 'v247'.
Oct 21 14:11:43 rbpi0 bluetoothd[443]: Starting SDP server
Oct 21 14:11:43 rbpi0 systemd[1]: Starting Rotate log files...
Oct 21 14:11:43 rbpi0 bluetoothd[443]: Bluetooth daemon 5.55
Oct 21 14:11:43 rbpi0 echo[455]: TEST
Oct 21 14:11:43 rbpi0 systemd[1]: Starting test...
Oct 21 14:11:42 rbpi0 systemd[1]: Starting Online ext4 Metadata Check for All Filesystems...
Oct 21 14:11:42 rbpi0 kernel: rtc-rv3028 1-0052: setting system clock to 2023-10-21T14:11:42 UTC (1697897502)
```

How can I avoid my script to run during the boot sequence but run only at `*:30`?


  [1]: https://askubuntu.com/a/1306410