+ may not be a variable, since it must
+ be a literal and absolute path
+ name.</para>
+
+ <para>Optionally, if the absolute file
+ name is prefixed with
+ '<literal>@</literal>', the second token
+ will be passed as
+ <literal>argv[0]</literal> to the
+ executed process, followed by the
+ further arguments specified. If the
+ absolute file name is prefixed with
+ '<literal>-</literal>' an exit code of
+ the command normally considered a
+ failure (i.e. non-zero exit status or
+ abnormal exit due to signal) is ignored
+ and considered success. If both
+ '<literal>-</literal>' and
+ '<literal>@</literal>' are used they
+ can appear in either order.</para>
+
+ <para>Note that this setting does not
+ directly support shell command
+ lines. If shell command lines are to
+ be used they need to be passed
+ explicitly to a shell implementation
+ of some kind. Example:
+ <literal>ExecStart=/bin/sh -c 'dmesg | tac'</literal></para>
+
+ <para>For services run by a user
+ instance of systemd the special
+ environment variable
+ <literal>MANAGERPID</literal> is set
+ to the PID of the systemd
+ instance.</para>
+ </listitem>