1SYSTEMD.SYNTAX(7)               systemd.syntax               SYSTEMD.SYNTAX(7)
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NAME

6       systemd.syntax - General syntax of systemd configuration files
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INTRODUCTION

9       This page describes the basic principles of configuration files used by
10       systemd(1) and related programs for:
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12       ·   systemd unit files, see systemd.unit(5), systemd.service(5),
13           systemd.socket(5), systemd.device(5), systemd.mount(5),
14           systemd.automount(5), systemd.swap(5), systemd.target(5),
15           systemd.path(5), systemd.timer(5), systemd.slice(5),
16           systemd.scope(5), systemd.nspawn(5)
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18       ·   link files, see systemd.link(5)
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20       ·   netdev and network files, see systemd.netdev(5), systemd.network(5)
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22       ·   daemon config files, see systemd-system.conf(5), systemd-
23           user.conf(5), logind.conf(5), journald.conf(5), journal-
24           remote.conf(5), journal-upload.conf(5), systemd-sleep.conf(5),
25           timesyncd.conf(5)
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27       The syntax is inspired by XDG Desktop Entry Specification[1] .desktop
28       files, which are in turn inspired by Microsoft Windows .ini files.
29
30       Each file is a plain text file divided into sections, with
31       configuration entries in the style key=value. Whitespace immediately
32       before or after the "=" is ignored. Empty lines and lines starting with
33       "#" or ";" are ignored, which may be used for commenting.
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35       Lines ending in a backslash are concatenated with the following line
36       while reading and the backslash is replaced by a space character. This
37       may be used to wrap long lines. The limit on line length is very large
38       (currently 1 MB), but it is recommended to avoid such long lines and
39       use multiple directives, variable substitution, or other mechanism as
40       appropriate for the given file type. When a comment line or lines
41       follow a line ending with a backslash, the comment block is ignored, so
42       the continued line is concatenated with whatever follows the comment
43       block.
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45       Example 1.
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47           [Section A]
48           KeyOne=value 1
49           KeyTwo=value 2
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51           # a comment
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53           [Section B]
54           Setting="something" "some thing" "..."
55           KeyTwo=value 2 \
56                  value 2 continued
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58           [Section C]
59           KeyThree=value 3\
60           # this line is ignored
61           ; this line is ignored too
62                  value 3 continued
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64       Boolean arguments used in configuration files can be written in various
65       formats. For positive settings the strings 1, yes, true and on are
66       equivalent. For negative settings, the strings 0, no, false and off are
67       equivalent.
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69       Time span values encoded in configuration files can be written in
70       various formats. A stand-alone number specifies a time in seconds. If
71       suffixed with a time unit, the unit is honored. A concatenation of
72       multiple values with units is supported, in which case the values are
73       added up. Example: "50" refers to 50 seconds; "2min 200ms" refers to 2
74       minutes and 200 milliseconds, i.e. 120200 ms. The following time units
75       are understood: "s", "min", "h", "d", "w", "ms", "us". For details see
76       systemd.time(7).
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78       Various settings are allowed to be specified more than once, in which
79       case the interpretation depends on the setting. Often, multiple
80       settings form a list, and setting to an empty value "resets", which
81       means that previous assignments are ignored. When this is allowed, it
82       is mentioned in the description of the setting. Note that using
83       multiple assignments to the same value makes the file incompatible with
84       parsers for the XDG .desktop file format.
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SEE ALSO

87       systemd.time(7)
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NOTES

90        1. XDG Desktop Entry Specification
91           http://standards.freedesktop.org/desktop-entry-spec/latest/
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95systemd 246                                                  SYSTEMD.SYNTAX(7)
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