-<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
-<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+<?xml version='1.0'?>
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
<!ENTITY % entities SYSTEM "custom-entities.ent" >
%entities;
]>
-
<!-- SPDX-License-Identifier: LGPL-2.1+ -->
<refentry id="systemd.syntax">
<para>Each file is a plain text file divided into sections, with configuration entries in the
style <replaceable>key</replaceable>=<replaceable>value</replaceable>.
- Empty lines and lines starting with <literal>#</literal> or <literal>;</literal> are
+ Whitespace immediately before or after the <literal>=</literal> is ignored. Empty lines and lines starting with <literal>#</literal> or <literal>;</literal> are
ignored, which may be used for commenting.</para>
<para>Lines ending in a backslash are concatenated with the following line while reading and the
backslash is replaced by a space character. This may be used to wrap long lines. The limit on
line length is very large (currently 1 MB), but it is recommended to avoid such long lines and
use multiple directives, variable substitution, or other mechanism as appropriate for the given
- file type.</para>
+ file type. When a comment line or lines follow a line ending with a backslash, the comment block
+ is ignored, so the continued line is concatenated with whatever follows the comment block.</para>
<example><programlisting>[Section A]
KeyOne=value 1
Setting="something" "some thing" "…"
KeyTwo=value 2 \
value 2 continued
+
+[Section C]
+KeyThree=value 2\
+# this line is ignored
+; this line is ignored too
+ value 2 continued
</programlisting></example>
+ <para>Boolean arguments used in configuration files can be written in
+ various formats. For positive settings the strings
+ <option>1</option>, <option>yes</option>, <option>true</option>
+ and <option>on</option> are equivalent. For negative settings, the
+ strings <option>0</option>, <option>no</option>,
+ <option>false</option> and <option>off</option> are
+ equivalent.</para>
+
+ <para>Time span values encoded in configuration 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: <literal>50</literal> refers to 50 seconds; <literal>2min 200ms</literal> refers to
+ 2 minutes and 200 milliseconds, i.e. 120200 ms. The following time units are understood:
+ <literal>s</literal>, <literal>min</literal>, <literal>h</literal>, <literal>d</literal>,
+ <literal>w</literal>, <literal>ms</literal>, <literal>us</literal>. For details see
+ <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
+
<para>Various settings are allowed to be specified more than once, in which case the
interpretation depends on the setting. Often, multiple settings form a list, and setting to an
empty value "resets", which means that previous assignments are ignored. When this is allowed,
file format.</para>
</refsect1>
+ <refsect1>
+ <title>See Also</title>
+ <para>
+ <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+ </para>
+ </refsect1>
+
</refentry>