<para>If <literal>replace-irreversibly</literal> is specified,
operate like <literal>replace</literal>, but also mark the new
jobs as irreversible. This prevents future conflicting
<para>If <literal>replace-irreversibly</literal> is specified,
operate like <literal>replace</literal>, but also mark the new
jobs as irreversible. This prevents future conflicting
- transactions from replacing these jobs. The jobs can still be
- cancelled using the <command>cancel</command> command.</para>
+ transactions from replacing these jobs (or even being enqueued
+ while the irreversible jobs are still pending). Irreversible
+ jobs can still be cancelled using the <command>cancel</command>
+ command.</para>
<para><literal>isolate</literal> is only valid for start
operations and causes all other units to be stopped when the
<para><literal>isolate</literal> is only valid for start
operations and causes all other units to be stopped when the
control processes. Note that there is only one control
process per unit at a time, as only one state change is
executed at a time. For services of type
control processes. Note that there is only one control
process per unit at a time, as only one state change is
executed at a time. For services of type
by the manager for <varname>ExecStart=</varname> is a
control process, while the process ultimately forked off by
that one is then considered the main process of the unit (if
it can be determined). This is different for service units
of other types, where the process forked off by the manager
for <varname>ExecStart=</varname> is always the main process
by the manager for <varname>ExecStart=</varname> is a
control process, while the process ultimately forked off by
that one is then considered the main process of the unit (if
it can be determined). This is different for service units
of other types, where the process forked off by the manager
for <varname>ExecStart=</varname> is always the main process
- itself. A service unit consists of no or one main process,
- no or one control process plus any number of additional
+ itself. A service unit consists of zero or one main process,
+ zero or one control process plus any number of additional
are defined (which are the invocations of
<filename>/usr/bin/mount</filename> and
<filename>/usr/bin/umount</filename>), but no main process
are defined (which are the invocations of
<filename>/usr/bin/mount</filename> and
<filename>/usr/bin/umount</filename>), but no main process
safe option to request an immediate reboot. If
<option>--force</option> is specified twice for these
operations, they will be executed immediately without
safe option to request an immediate reboot. If
<option>--force</option> is specified twice for these
operations, they will be executed immediately without
systems. Warning: specifying <option>--force</option> twice
with any of these operations might result in data
loss.</para>
systems. Warning: specifying <option>--force</option> twice
with any of these operations might result in data
loss.</para>
<para>Show terse runtime status information about one or
more units, followed by most recent log data from the
journal. If no units are specified, show system status. If
<para>Show terse runtime status information about one or
more units, followed by most recent log data from the
journal. If no units are specified, show system status. If
all units (subject to limitations specified with
<option>-t</option>). If a PID is passed, show information
about the unit the process belongs to.</para>
all units (subject to limitations specified with
<option>-t</option>). If a PID is passed, show information
about the unit the process belongs to.</para>
activation of the unit, including manual activation. Use
this option with care. This honors the
<option>--runtime</option> option to only mask temporarily
activation of the unit, including manual activation. Use
this option with care. This honors the
<option>--runtime</option> option to only mask temporarily
(designated as <replaceable>NAME</replaceable>), or multiple
unit specifications (designated as
<replaceable>PATTERN</replaceable>...). In the first case, the
(designated as <replaceable>NAME</replaceable>), or multiple
unit specifications (designated as
<replaceable>PATTERN</replaceable>...). In the first case, the