<varlistentry>
<term><varname>Persistent=</varname></term>
- <listitem><para>Takes a boolean argument. If true, the time
- when the service unit was last triggered is stored on disk.
- When the timer is activated, the service unit is triggered
- immediately if it would have been triggered at least once
- during the time when the timer was inactive. This is useful to
- catch up on missed runs of the service when the machine was
- off. Note that this setting only has an effect on timers
- configured with <varname>OnCalendar=</varname>. Defaults
- to <varname>false</varname>.
- </para></listitem>
+ <listitem><para>Takes a boolean argument. If true, the time when the service unit was last triggered
+ is stored on disk. When the timer is activated, the service unit is triggered immediately if it
+ would have been triggered at least once during the time when the timer was inactive. This is useful
+ to catch up on missed runs of the service when the system was powered down. Note that this setting
+ only has an effect on timers configured with <varname>OnCalendar=</varname>. Defaults to
+ <varname>false</varname>.</para>
+
+ <para>Use <command>systemctl clean --what=state …</command> on the timer unit to remove the timestamp
+ file maintained by this option from disk. In particular, use this command before uninstalling a timer
+ unit. See
+ <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> for
+ details.</para></listitem>
</varlistentry>
<varlistentry>