chiark / gitweb /
man: remove advice to avoid setting the same var more than once
[elogind.git] / man / systemd.service.xml
index 8eda85f62db6546684545c5a2082b5cdccd5781d..f6b9fe2965af863774b8c22a8db3bd67a12f3099 100644 (file)
@@ -76,8 +76,8 @@
                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                 which define the way the processes of the service are
                 terminated, and in
-                <citerefentry><refentrytitle>systemd.cgroup</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
-                which configure control group settings for the
+                <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+                which configure resource control settings for the
                 processes of the service.</para>
 
                 <para>Unless <varname>DefaultDependencies=</varname>
                                 <term><varname>ExecStart=</varname></term>
                                 <listitem><para>Commands with their
                                 arguments that are executed when this
-                                service is started. The first
-                                argument must be an absolute path
-                                name.</para>
+                                service is started. For each of the
+                                specified commands, the first argument
+                                must be an absolute and literal path
+                                to an executable.</para>
 
                                 <para>When <varname>Type</varname> is
                                 not <option>oneshot</option>, only one
                                 (these semicolons must be passed as
                                 separate words). Alternatively, this
                                 directive may be specified more than
-                                once with the same effect. However,
-                                the latter syntax is not recommended
-                                for compatibility with parsers
-                                suitable for XDG
-                                <filename>.desktop</filename> files.
+                                once with the same effect.
                                 Lone semicolons may be escaped as
                                 <literal>\;</literal>. If the empty
                                 string is assigned to this option, the
                                 prior assignments of this option will
                                 have no effect.</para>
 
+                                <para>Each command line is split on
+                                whitespace, with the first item being
+                                the command to execute, and the
+                                subsequent items being the arguments.
+                                Double quotes ("...") and single
+                                quotes ('...') may be used, in which
+                                case everything until the next
+                                matching quote becomes part of the
+                                same argument. Quotes themselves are
+                                removed after parsing. In addition, a
+                                trailing backslash
+                                (<literal>\</literal>) may be used to
+                                merge lines. This syntax is intended
+                                to be very similar to shell syntax,
+                                but only the meta-characters and
+                                expansions described in the following
+                                paragraphs are understood.
+                                Specifically, redirection using
+                                <literal>&lt;</literal>,
+                                <literal>&lt;&lt;</literal>,
+                                <literal>&gt;</literal>, and
+                                <literal>&gt;&gt;</literal>, pipes
+                                using <literal>|</literal>, and
+                                running programs in the background
+                                using <literal>&amp;</literal>
+                                and <emphasis>other elements of shell
+                                syntax are not supported</emphasis>.
+                                </para>
+
                                 <para>If more than one command is
                                 specified, the commands are invoked
                                 one by one sequentially in the order
                                 <para>The command line accepts
                                 <literal>%</literal> specifiers as
                                 described in
-                                <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Note
-                                that the first argument of the command
-                                line (i.e. the program to execute) may
-                                not include specifiers.</para>
+                                <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+                                Note that the first argument of the
+                                command line (i.e. the program to
+                                execute) may not include
+                                specifiers.</para>
 
                                 <para>Basic environment variable
                                 substitution is supported. Use
                                 case it will be replaced by the value
                                 of the environment variable split up
                                 at whitespace, resulting in zero or
-                                more arguments. Note that the first
+                                more arguments. To pass a literal dollar sign,
+                                use <literal>$$</literal>. Note that the first
                                 argument (i.e. the program to execute)
-                                may not be a variable, since it must
-                                be a literal and absolute path
-                                name.</para>
+                                may not be a variable.</para>
 
                                 <para>Optionally, if the absolute file
                                 name is prefixed with
                                 <programlisting>ExecStart=/bin/sh -c 'dmesg | tac'
                                 </programlisting>
 
-                                <para>For services run by a user
-                                instance of systemd the special
-                                environment variable
-                                <varname>$MANAGERPID</varname> is set
-                                to the PID of the systemd
-                                instance.</para>
-                                </listitem>
+                                <para>Only select environment variables
+                                are set for executed commands. See
+                                <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+                                </para>
+
+                                <para>Example:</para>
+                                <programlisting>ExecStart=/bin/echo one ; /bin/echo "two two"
+                                </programlisting>
+                                <para>This will execute
+                                <command>/bin/echo</command> two
+                                times, each time with one argument,
+                                <literal>one</literal> and
+                                <literal>two two</literal>,
+                                respectively. Since two commands are
+                                specified
+                                <varname>Type=oneshot</varname> must
+                                be used.</para>
+
+                                <para>Example:</para>
+                                <programlisting>ExecStart=/bin/echo / &gt;/dev/null &amp; \; \
+/bin/ls
+                                </programlisting>
+                                <para>This will execute
+                                <command>/bin/echo</command> with five
+                                arguments: <literal>/</literal>,
+                                <literal>&gt;/dev/null</literal>,
+                                <literal>&amp;</literal>,
+                                <literal>;</literal>, and
+                                <literal>/bin/ls</literal>.</para>
+
+                                <para>Example:</para>
+                                <programlisting>Environment="ONE=one" 'TWO=two two'
+ExecStart=/bin/echo $ONE $TWO ${TWO}
+                                </programlisting>
+                                <para>This will execute
+                                <command>/bin/echo</command> with four
+                                arguments: <literal>one</literal>,
+                                <literal>two</literal>,
+                                <literal>two</literal>, and
+                                <literal>two two</literal>.</para>
+                              </listitem>
                         </varlistentry>
 
                         <varlistentry>
                                 Takes a unit-less value in seconds, or a
                                 time span value such as "5min
                                 20s". Pass 0 to disable the timeout
-                                logic. Defaults to 90s, except when
+                                logic. Defaults to <varname>TimeoutStartSec=</varname> from the
+                                manager configuration file, except when
                                 <varname>Type=oneshot</varname> is
-                                used in which case the timeout
+                                used, in which case the timeout
                                 is disabled by default.
                                 </para></listitem>
                         </varlistentry>
                                 Takes a unit-less value in seconds, or a
                                 time span value such as "5min
                                 20s". Pass 0 to disable the timeout
-                                logic. Defaults to 90s.
+                                logic. Defaults to <varname>TimeoutStartSec=</varname> from the
+                                manager configuration file.
                                 </para></listitem>
                         </varlistentry>
 
                                 these two options, this rate limiting
                                 may be modified. Use
                                 <varname>StartLimitInterval=</varname>
-                                to configure the checking interval
-                                (defaults to 10s, set to 0 to disable
+                                to configure the checking interval (defaults to
+                                <varname>DefaultStartLimitInterval=</varname> in
+                                manager configuration file, set to 0 to disable
                                 any kind of rate limiting). Use
                                 <varname>StartLimitBurst=</varname> to
                                 configure how many starts per interval
-                                are allowed (defaults to 5). These
+                                are allowed (defaults to
+                                <varname>DefaultStartLimitBurst=</varname> in
+                                manager configuration file). These
                                 configuration options are particularly
                                 useful in conjunction with
                                 <varname>Restart=</varname>, however
                                 range 0-99.</para></listitem>
                         </varlistentry>
 
-                        <varlistentry>
-                                <term><varname>FsckPassNo=</varname></term>
-                                <listitem><para>Set the fsck passno
-                                priority to use to order this service
-                                in relation to other file system
-                                checking services. This option is only
-                                necessary to fix ordering in relation
-                                to fsck jobs automatically created for
-                                all <filename>/etc/fstab</filename>
-                                entries with a value in the fs_passno
-                                column > 0. As such it should only be
-                                used as option for fsck
-                                services. Almost always it is a better
-                                choice to add explicit ordering
-                                directives via
-                                <varname>After=</varname> or
-                                <varname>Before=</varname>,
-                                instead. For more details see
-                                <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. If
-                                used, pass an integer value in the
-                                same range as
-                                <filename>/etc/fstab</filename>'s
-                                fs_passno column. See
-                                <citerefentry><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>
-                                for details.</para></listitem>
-                        </varlistentry>
-
                 </variablelist>
         </refsect1>
 
                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
-                          <citerefentry><refentrytitle>systemd.cgroup</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+                          <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
                   </para>