systemd.syntax(7)

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

NAME
       systemd.syntax - General syntax of systemd configuration files

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

       o   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)

       o   link files, see systemd.link(5)

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

       o   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 2\
           # this line is ignored
           ; this line is ignored too
                  value 2 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
       systemd.time(7)

NOTES
        1. XDG Desktop Entry Specification
           http://standards.freedesktop.org/desktop-entry-spec/latest/

systemd 245                                                  SYSTEMD.SYNTAX(7)