sections of the unit files.</para>
<para>In addition to the generic [Unit] and [Install]
- sections described here, each unit should have a
+ sections described here, each unit may have a
type-specific section, e.g. [Service] for a service
unit. See the respective man pages for more
information.</para>
<para>Time span values encoded in unit files can be
written in various formats. A stand-alone number
specifies a time in seconds. If suffixed with a time
- unit, the unit is honored. A concatenation of
- multiple values with units is supported, in which case
- the values are added up. Example: "50" refers to 50
+ unit, the unit is honored. A concatenation of multiple
+ values with units is supported, in which case the
+ values are added up. Example: "50" refers to 50
seconds; "2min 200ms" refers to 2 minutes plus 200
milliseconds, i.e. 120200ms. The following time units
- are understood: s, min, h, d, w, ms, us. For details see <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
+ are understood: s, min, h, d, w, ms, us. For details
+ see
+ <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
<para>Empty lines and lines starting with # or ; are
ignored. This may be used for commenting. Lines ending
line while reading and the backslash is replaced by a
space character. This may be used to wrap long lines.</para>
- <para>If a line starts with <option>.include</option>
- followed by a file name, the specified file will be
- parsed at this point. Make sure that the file that is
- included has the appropriate section headers before
- any directives.</para>
-
<para>Along with a unit file
- <filename>foo.service</filename> a directory
+ <filename>foo.service</filename> the directory
<filename>foo.service.wants/</filename> may exist. All
- units symlinked from such a directory are implicitly
- added as dependencies of type
+ unit files symlinked from such a directory are
+ implicitly added as dependencies of type
<varname>Wanted=</varname> to the unit. This is useful
to hook units into the start-up of other units,
- without having to modify their unit configuration
- files. For details about the semantics of
- <varname>Wanted=</varname> see below. The preferred
- way to create symlinks in the
- <filename>.wants/</filename> directory of a service is
- with the <command>enable</command> command of the
+ without having to modify their unit files. For details
+ about the semantics of <varname>Wanted=</varname> see
+ below. The preferred way to create symlinks in the
+ <filename>.wants/</filename> directory of a unit file
+ is with the <command>enable</command> command of the
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
tool which reads information from the [Install]
- section of unit files. (See below.) A similar
+ section of unit files (see below). A similar
functionality exists for <varname>Requires=</varname>
type dependencies as well, the directory suffix is
<filename>.requires/</filename> in this case.</para>
+ <para>Along with a unit file
+ <filename>foo.service</filename> a directory
+ <filename>foo.service.d/</filename> may exist. All
+ files with the suffix <filename>.conf</filename> from
+ this directory will be parsed after the file itself is
+ parsed. This is useful to alter or add configuration
+ settings to a unit, without having to modify their
+ unit files. Make sure that the file that is included
+ has the appropriate section headers before any
+ directive.</para>
+
+ <para>If a line starts with <option>.include</option>
+ followed by a file name, the specified file will be
+ parsed at this point. Make sure that the file that is
+ included has the appropriate section headers before
+ any directives.</para>
+
<para>Note that while systemd offers a flexible
dependency system between units it is recommended to
use this functionality only sparsely and instead rely
<para>To refer to the instance string from
within the configuration file you may use the special
<literal>%i</literal> specifier in many of the
- configuration options. Other specifiers exist, the
- full list is:</para>
-
- <table>
- <title>Specifiers available in unit files</title>
- <tgroup cols='3' align='left' colsep='1' rowsep='1'>
- <colspec colname="spec" />
- <colspec colname="mean" />
- <colspec colname="detail" />
- <thead>
- <row>
- <entry>Specifier</entry>
- <entry>Meaning</entry>
- <entry>Details</entry>
- </row>
- </thead>
- <tbody>
- <row>
- <entry><literal>%n</literal></entry>
- <entry>Full unit name</entry>
- <entry></entry>
- </row>
- <row>
- <entry><literal>%N</literal></entry>
- <entry>Unescaped full unit name</entry>
- <entry></entry>
- </row>
- <row>
- <entry><literal>%p</literal></entry>
- <entry>Prefix name</entry>
- <entry>This refers to the string before the @, i.e. "getty" in the example above, where "tty3" is the instance name.</entry>
- </row>
- <row>
- <entry><literal>%P</literal></entry>
- <entry>Unescaped prefix name</entry>
- <entry></entry>
- </row>
- <row>
- <entry><literal>%i</literal></entry>
- <entry>Instance name</entry>
- <entry>This is the string between the @ character and the suffix.</entry>
- </row>
- <row>
- <entry><literal>%I</literal></entry>
- <entry>Unescaped instance name</entry>
- <entry></entry>
- </row>
- <row>
- <entry><literal>%f</literal></entry>
- <entry>Unescaped file name</entry>
- <entry>This is either the unescaped instance name (if set) with / prepended (if necessary), or the prefix name similarly prepended with /.</entry>
- </row>
- <row>
- <entry><literal>%c</literal></entry>
- <entry>Control group path of the unit</entry>
- <entry></entry>
- </row>
- <row>
- <entry><literal>%r</literal></entry>
- <entry>Root control group path of systemd</entry>
- <entry></entry>
- </row>
- <row>
- <entry><literal>%R</literal></entry>
- <entry>Parent directory of the root control group path of systemd</entry>
- <entry></entry>
- </row>
- <row>
- <entry><literal>%t</literal></entry>
- <entry>Runtime socket dir</entry>
- <entry>This is either /run (for the system manager) or $XDG_RUNTIME_DIR (for user managers).</entry>
- </row>
- <row>
- <entry><literal>%u</literal></entry>
- <entry>User name</entry>
- <entry>This is the name of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
- </row>
- <row>
- <entry><literal>%U</literal></entry>
- <entry>User uid</entry>
- <entry>This is the uid of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
- </row>
- <row>
- <entry><literal>%h</literal></entry>
- <entry>User home directory</entry>
- <entry>This is the home directory of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
- </row>
- <row>
- <entry><literal>%s</literal></entry>
- <entry>User shell</entry>
- <entry>This is the shell of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
- </row>
- <row>
- <entry><literal>%m</literal></entry>
- <entry>Machine ID</entry>
- <entry>The machine ID of the running system, formatted as string. See <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more information.</entry>
- </row>
- <row>
- <entry><literal>%b</literal></entry>
- <entry>Boot ID</entry>
- <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
- </row>
- <row>
- <entry><literal>%H</literal></entry>
- <entry>Host name</entry>
- <entry>The host name of the running system.</entry>
- </row>
- </tbody>
- </tgroup>
- </table>
+ configuration options. See below for details.</para>
<para>If a unit file is empty (i.e. has the file size
0) or is symlinked to <filename>/dev/null</filename>
<ulink
url="http://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise">Interface
Stability Promise</ulink>.</para>
+
</refsect1>
<refsect1>
reference documentation that explains
what the unit's purpose is, followed
by how it is configured, followed by
- any other related
- documentation.</para></listitem>
+ any other related documentation. This
+ option may be specified more than once
+ in which case the specified list of
+ URIs is merged. If the empty string is
+ assigned to this option the list is
+ reset and all prior assignments will
+ have no effect.</para></listitem>
</varlistentry>
<varlistentry>
an exclamation mark.</para>
<para><varname>ConditionACPower=</varname>
- may may be used to check whether the
- system has AC power, or is exlcusively
+ may be used to check whether the
+ system has AC power, or is exclusively
battery powered at the time of
activation of the unit. This takes a
boolean argument. If set to
pipe symbol must be passed first, the
exclamation second. Except for
<varname>ConditionPathIsSymbolicLink=</varname>,
- all path checks follow
- symlinks.</para></listitem>
+ all path checks follow symlinks. If
+ any of these options is assigned the
+ empty string the list of conditions is
+ reset completely, all previous
+ condition settings (of any kind) will
+ have no effect.</para></listitem>
</varlistentry>
<varlistentry>
</refsect1>
+ <refsect1>
+ <title>Specifiers</title>
+
+ <para>Many settings resolve specifiers which may be
+ used to write generic unit files referring to runtime
+ or unit parameters that are replaced when the unit
+ files are loaded. The following specifiers are
+ understood:</para>
+
+ <table>
+ <title>Specifiers available in unit files</title>
+ <tgroup cols='3' align='left' colsep='1' rowsep='1'>
+ <colspec colname="spec" />
+ <colspec colname="mean" />
+ <colspec colname="detail" />
+ <thead>
+ <row>
+ <entry>Specifier</entry>
+ <entry>Meaning</entry>
+ <entry>Details</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry><literal>%n</literal></entry>
+ <entry>Full unit name</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry><literal>%N</literal></entry>
+ <entry>Unescaped full unit name</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry><literal>%p</literal></entry>
+ <entry>Prefix name</entry>
+ <entry>For instantiated units this refers to the string before the @. For non-instantiated units this refers to to the name of the unit with the type suffix removed.</entry>
+ </row>
+ <row>
+ <entry><literal>%P</literal></entry>
+ <entry>Unescaped prefix name</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry><literal>%i</literal></entry>
+ <entry>Instance name</entry>
+ <entry>For instantiated units: this is the string between the @ character and the suffix.</entry>
+ </row>
+ <row>
+ <entry><literal>%I</literal></entry>
+ <entry>Unescaped instance name</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry><literal>%f</literal></entry>
+ <entry>Unescaped file name</entry>
+ <entry>This is either the unescaped instance name (if applicable) with / prepended (if applicable), or the prefix name similarly prepended with /.</entry>
+ </row>
+ <row>
+ <entry><literal>%c</literal></entry>
+ <entry>Control group path of the unit</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry><literal>%r</literal></entry>
+ <entry>Root control group path of systemd</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry><literal>%R</literal></entry>
+ <entry>Parent directory of the root control group path of systemd</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry><literal>%t</literal></entry>
+ <entry>Runtime socket dir</entry>
+ <entry>This is either <filename>/run</filename> (for the system manager) or <literal>$XDG_RUNTIME_DIR</literal> (for user managers).</entry>
+ </row>
+ <row>
+ <entry><literal>%u</literal></entry>
+ <entry>User name</entry>
+ <entry>This is the name of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
+ </row>
+ <row>
+ <entry><literal>%U</literal></entry>
+ <entry>User UID</entry>
+ <entry>This is the UID of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
+ </row>
+ <row>
+ <entry><literal>%h</literal></entry>
+ <entry>User home directory</entry>
+ <entry>This is the home directory of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
+ </row>
+ <row>
+ <entry><literal>%s</literal></entry>
+ <entry>User shell</entry>
+ <entry>This is the shell of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry>
+ </row>
+ <row>
+ <entry><literal>%m</literal></entry>
+ <entry>Machine ID</entry>
+ <entry>The machine ID of the running system, formatted as string. See <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more information.</entry>
+ </row>
+ <row>
+ <entry><literal>%b</literal></entry>
+ <entry>Boot ID</entry>
+ <entry>The boot ID of the running system, formatted as string. See <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> for more information.</entry>
+ </row>
+ <row>
+ <entry><literal>%H</literal></entry>
+ <entry>Host name</entry>
+ <entry>The host name of the running system.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </refsect1>
+
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.snapshot</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+ <citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
</para>
</refsect1>
~ianmdlvl / elogind.git / blobdiff