systemd.syntax(7) — Linux manual page


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

NAME         top

       systemd.syntax - General syntax of systemd configuration files

INTRODUCTION         top

       This page describes the basic principles of configuration files used
       by systemd(1) and related programs for:

       •   systemd unit files, see systemd.unit(5), systemd.service(5),
           systemd.socket(5), systemd.device(5), systemd.mount(5),
           systemd.automount(5), systemd.swap(5),,
           systemd.path(5), systemd.timer(5), systemd.slice(5),
           systemd.scope(5), systemd.nspawn(5)

       •   link files, see

       •   netdev and network files, see systemd.netdev(5),

       •   daemon config files, see systemd-system.conf(5),
           systemd-user.conf(5), logind.conf(5), journald.conf(5),
           journal-remote.conf(5), journal-upload.conf(5),
           systemd-sleep.conf(5), timesyncd.conf(5)

       The syntax is inspired by XDG Desktop Entry Specification[1] .desktop
       files, which are in turn inspired by Microsoft Windows .ini files.

       Each file is a plain text file divided into sections, with
       configuration entries in the style key=value. Whitespace immediately
       before or after the "=" is ignored. Empty lines and lines starting
       with "#" or ";" are ignored, which may be used for commenting.

       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. 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.

       Example 1.

           [Section A]
           KeyOne=value 1
           KeyTwo=value 2

           # a comment

           [Section B]
           Setting="something" "some thing" "..."
           KeyTwo=value 2 \
                  value 2 continued

           [Section C]
           KeyThree=value 3\
           # this line is ignored
           ; this line is ignored too
                  value 3 continued

       Boolean arguments used in configuration files can be written in
       various formats. For positive settings the strings 1, yes, true and
       on are equivalent. For negative settings, the strings 0, no, false
       and off are equivalent.

       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: "50" refers to 50 seconds; "2min 200ms" refers to
       2 minutes and 200 milliseconds, i.e. 120200 ms. The following time
       units are understood: "s", "min", "h", "d", "w", "ms", "us". For
       details see systemd.time(7).

       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, it
       is mentioned in the description of the setting. Note that using
       multiple assignments to the same value makes the file incompatible
       with parsers for the XDG .desktop file format.

SEE ALSO         top


NOTES         top

        1. XDG Desktop Entry Specification

COLOPHON         top

       This page is part of the systemd (systemd system and service manager)
       project.  Information about the project can be found at 
       ⟨⟩.  If you have a bug
       report for this manual page, see
       ⟨⟩.  This
       page was obtained from the project's upstream Git repository
       ⟨⟩ on 2020-11-01.  (At that
       time, the date of the most recent commit that was found in the repos‐
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       this HTML version of the page, or you believe there is a better or
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       the original manual page), send a mail to

systemd 247                                                SYSTEMD.SYNTAX(7)

Pages that refer to this page: journald.conf(5)journald@.conf(5)journald.conf.d(5)journal-remote.conf(5)journal-remote.conf.d(5)journal-upload.conf(5)journal-upload.conf.d(5)logind.conf(5)logind.conf.d(5)oomd.conf(5)oomd.conf.d(5)sleep.conf.d(5)system.conf.d(5)