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NAME | INTRODUCTION | SEE ALSO | NOTES | COLOPHON |
SYSTEMD.SYNTAX(7) systemd.syntax SYSTEMD.SYNTAX(7)
systemd.syntax - General syntax of systemd configuration files
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.target(5),
systemd.path(5), systemd.timer(5), systemd.slice(5),
systemd.scope(5), systemd.nspawn(5)
· link files, see systemd.link(5)
· netdev and network files, see systemd.netdev(5),
systemd.network(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.
systemd.time(7)
1. XDG Desktop Entry Specification
http://standards.freedesktop.org/desktop-entry-spec/latest/
This page is part of the systemd (systemd system and service manager)
project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a bug
report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩. This
page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2020-08-13. (At that
time, the date of the most recent commit that was found in the repos‐
itory was 2020-08-11.) If you discover any rendering problems in
this HTML version of the page, or you believe there is a better or
more up-to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not part
of the original manual page), send a mail to man-pages@man7.org
systemd 246 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) , sleep.conf.d(5) , system.conf.d(5) , systemd.link(5) , systemd.netdev(5) , systemd.network(5) , systemd.nspawn(5) , systemd-sleep.conf(5) , systemd-system.conf(5) , systemd.unit(5) , systemd-user.conf(5) , timesyncd.conf(5) , timesyncd.conf.d(5) , user.conf.d(5) , 30-systemd-environment-d-generator(7) , systemd.index(7)