<varlistentry>
<term><varname>StandardError=</varname></term>
<listitem><para>Controls where file
- descriptor 2 (standard error) of the
+ descriptor 2 (STDERR) of the
executed processes is connected to.
The available options are identical to
those of
tty.</para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><varname>$MAINPID</varname></term>
+
+ <listitem><para>The PID of the units
+ main process if it is known. This is
+ only set for control processes as
+ invoked by
+ <varname>ExecReload=</varname> and
+ similar. </para></listitem>
+ </varlistentry>
+
<varlistentry>
<term><varname>$MANAGERPID</varname></term>