SYSTEMD.PRESET(5)                               SYSTEMD.PRESET(5)

     NAME
          systemd.preset - Service enablement presets

     SYNOPSIS
          /etc/systemd/system-preset/*.preset

          /run/systemd/system-preset/*.preset

          /lib/systemd/system-preset/*.preset

          /etc/systemd/user-preset/*.preset

          /run/systemd/user-preset/*.preset

          /usr/lib/systemd/user-preset/*.preset

     DESCRIPTION
          Preset files may be used to encode policy which units shall
          be enabled by default and which ones shall be disabled. They
          are read by systemctl preset (for more information see
          systemctl(1)) which uses this information to enable or
          disable a unit according to preset policy.  systemctl preset
          is used by the post install scriptlets of RPM packages (or
          other OS package formats), to enable/disable specific units
          by default on package installation, enforcing distribution,
          spin or administrator preset policy. This allows choosing a
          certain set of units to be enabled/disabled even before
          installing the actual package.

          For more information on the preset logic please have a look
          at the m[blue]Presetsm[][1] document.

          It is not recommended to ship preset files within the
          respective software packages implementing the units, but
          rather centralize them in a distribution or spin default
          policy, which can be amended by administrator policy.

          If no preset files exist, systemctl preset will enable all
          units that are installed by default. If this is not desired
          and all units shall rather be disabled, it is necessary to
          ship a preset file with a single, catchall "disable *" line.
          (See example 1, below.)

     PRESET FILE FORMAT
          The preset files contain a list of directives consisting of
          either the word "enable" or "disable" followed by a space
          and a unit name (possibly with shell style wildcards),
          separated by newlines. Empty lines and lines whose first
          non-whitespace character is "#" or ";" are ignored. Multiple
          instance names for unit templates may be specified as a

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     SYSTEMD.PRESET(5)                               SYSTEMD.PRESET(5)

          space separated list at the end of the line instead of the
          customary position between "@" and the unit suffix.

          Presets must refer to the "real" unit file, and not to any
          aliases. See systemd.unit(5) for a description of unit
          aliasing.

          Two different directives are understood: "enable" may be
          used to enable units by default, "disable" to disable units
          by default.

          If multiple lines apply to a unit name, the first matching
          one takes precedence over all others.

          Each preset file shall be named in the style of
          <priority>-<policy-name>.preset. Files in /etc/ override
          files with the same name in /usr/lib/ and /run/. Files in
          /run/ override files with the same name in /lib/. Packages
          should install their preset files in /lib/. Files in /etc/
          are reserved for the local administrator, who may use this
          logic to override the preset files installed by vendor
          packages. All preset files are sorted by their filename in
          lexicographic order, regardless of which of the directories
          they reside in. If multiple files specify the same unit
          name, the entry in the file with the lexicographically
          earliest name will be applied. It is recommended to prefix
          all filenames with a two-digit number and a dash, to
          simplify the ordering of the files.

          If the administrator wants to disable a preset file supplied
          by the vendor, the recommended way is to place a symlink to
          /dev/null in /etc/systemd/system-preset/ bearing the same
          filename.

     EXAMPLES
          Example 1. Default to off

              # /lib/systemd/system-preset/99-default.preset

              disable *

          This disables all units. Due to the filename prefix "99-",
          it will be read last and hence can easily be overridden by
          spin or administrator preset policy.

          Example 2. Enable multiple template instances

              # /lib/systemd/system-preset/80-dirsrv.preset

              enable dirsrv@.service foo bar baz

          This enables all three of dirsrv@foo.service,

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     SYSTEMD.PRESET(5)                               SYSTEMD.PRESET(5)

          dirsrv@bar.service and dirsrv@baz.service.

          Example 3. A GNOME spin

              # /lib/systemd/system-preset/50-gnome.preset

              enable gdm.service
              enable colord.service
              enable accounts-daemon.service
              enable avahi-daemon.*

          This enables the three mentioned units, plus all
          avahi-daemon regardless of which unit type. A file like this
          could be useful for inclusion in a GNOME spin of a
          distribution. It will ensure that the units necessary for
          GNOME are properly enabled as they are installed. It leaves
          all other units untouched, and subject to other (later)
          preset files, for example like the one from the first
          example above.

          Example 4. Administrator policy

              # /etc/systemd/system-preset/00-lennart.preset

              enable httpd.service
              enable sshd.service
              enable postfix.service
              disable *

          This enables three specific services and disables all
          others. This is useful for administrators to specifically
          select the units to enable, and disable all others. Due to
          the filename prefix "00-" it will be read early and override
          all other preset policy files.

     SEE ALSO
          systemd(1), systemctl(1), systemd-delta(1)

     NOTES
           1. Presets
              https://www.freedesktop.org/wiki/Software/systemd/Preset

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