IN A previous post, I showed how to set up a scheduled notification every twenty minutes of using the computer, to help follow the 20-20-20 rule to lessen eyestrain.
In this post, I will show the equivalent for Linux. Specifically, using systemd timers. It's very similar in structure to the previous post:
- Set up a service unit for the notification
- Set up a timer unit to schedule the service
- Run commands to enable the timer
First, the service unit:
# ~/.config/systemd/user/twenty.service [Unit] Description=20-20-20 rule notifier [Service] ExecStart=/usr/bin/notify-send --hint int:transient:1 '20-20-20 rule' 'Take a break!'
This is a declarative equivalent of a shell script that contains the command to run. The important part is the last line, which contains the actual command. Notice that it has a 'hint', a typed key-value pair setting which will ensure that the notification doesn't stick around in the desktop environment's notification history after it disappears from the screen. This hint is documented here.
Remember to place the file in exactly the directory shown above. You will probably need to create it first, with:
mkdir -p ~/.config/systemd/user
Second, the timer unit:
# ~/.config/systemd/user/twenty.timer [Unit] Description=20-20-20 rule [Timer] OnCalendar=*:0,20,40:00 [Install] WantedBy=timers.target
This declares a schedule to run the
twenty.service unit on (the service name is implicitly understood from the name of the timer file).
The two significant parts of this timer unit are:
OnCalendar=property which sets the schedule. This property can understand various date and time formats, but in this case we are using
*meaning run every hour; the
0,20,40meaning run on the zeroth, twentieth, and fortieth minutes; and the
00meaning run on the zeroth second. This translates to: run every twenty minutes.
WantedBy=property which describes when the timer should be enabled on system boot. In this case it says: enable this timer when enabling all other timers on boot.
Finally, enable the timer immediately without needing to reboot the system:
$ systemctl daemon-reload --user # Tell systemd about the new units $ systemctl enable --user --now twenty.timer # Install the timer
This should set up a symbolic link to the timer, thus installing and enabling it. Note that we are using the
--user flag which means enable this timer for this user only, not for the entire system (i.e. all users, which would require admin privileges). The
--now flag also immediately activates the timer.
Check that the timer is active:
$ systemctl list-timers --user NEXT LEFT LAST PASSED UNIT ACTIVATES Sun 2020-10-11 20:40:00 EDT 15min left Sun 2020-10-11 20:20:50 EDT 4min 7s ago twenty.timer twenty.service Mon 2020-10-12 10:33:34 EDT 14h left Sat 2020-10-10 20:20:28 EDT 24h ago systemd-tmpfiles-clean.timer systemd-tmpfiles-clean.service n/a n/a Sat 2020-10-10 20:17:29 EDT 24h ago grub-boot-success.timer grub-boot-success.service 3 timers listed. Pass --all to see loaded but inactive timers, too.
This listing shows when the timer will run next.
If you need to disable the timer:
$ systemctl disable --user twenty.timer # Install the timer
If you need to edit and reload the timer, you can disable, then edit, then daemon-reload, then enable as shown above.
Top comments (2)
You can try workrave too, it's also for RSI in general and much heavier than yours solution of course 😁
Cool, thank you. I'll check it out sometime.