ENVIRONMENT.D(5)                                 ENVIRONMENT.D(5)

          environment.d - Definition of user service environment






          Configuration files in the environment.d/ directories
          contain lists of environment variable assignments for
          services started by the systemd user instance.  systemd-
          environment-d-generator(8) parses them and updates the
          environment exported by the systemd user instance. See below
          for an discussion of which processes inherit those

          It is recommended to use numerical prefixes for file names
          to simplify ordering.

          For backwards compatibility, a symlink to /etc/environment
          is installed, so this file is also parsed.

          Configuration files are read from directories in /etc/,
          /run/, /usr/local/lib/, and /lib/, in order of precedence,
          as listed in the SYNOPSIS section above. Files must have the
          ".conf" extension. Files in /etc/ override files with the
          same name in /run/, /usr/local/lib/, and /lib/. Files in
          /run/ override files with the same name under /usr/.

          All configuration files are sorted by their filename in
          lexicographic order, regardless of which of the directories
          they reside in. If multiple files specify the same option,
          the entry in the file with the lexicographically latest name
          will take precedence. Thus, the configuration in a certain
          file may either be replaced completely (by placing a file
          with the same name in a directory with higher priority), or
          individual settings might be changed (by specifying
          additional settings in a file with a different name that is
          ordered later).

          Packages should install their configuration files in
          /usr/lib/ (distribution packages) or /usr/local/lib/ (local

     Page 1                     systemd 247          (printed 5/26/22)

     ENVIRONMENT.D(5)                                 ENVIRONMENT.D(5)

          installs). Files in /etc/ are reserved for the local
          administrator, who may use this logic to override the
          configuration files installed by vendor packages. 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 configuration file
          supplied by the vendor, the recommended way is to place a
          symlink to /dev/null in the configuration directory in
          /etc/, with the same filename as the vendor configuration
          file. If the vendor configuration file is included in the
          initrd image, the image has to be regenerated.

          The configuration files contain a list of "KEY=VALUE"
          environment variable assignments, separated by newlines. The
          right hand side of these assignments may reference
          previously defined environment variables, using the
          "${OTHER_KEY}" and "$OTHER_KEY" format. It is also possible
          to use "${FOO:-DEFAULT_VALUE}" to expand in the same way as
          "${FOO}" unless the expansion would be empty, in which case
          it expands to DEFAULT_VALUE, and use
          "${FOO:+ALTERNATE_VALUE}" to expand to ALTERNATE_VALUE as
          long as "${FOO}" would have expanded to a non-empty value.
          No other elements of shell syntax are supported.

          Each KEY must be a valid variable name. Empty lines and
          lines beginning with the comment character "#" are ignored.

          Example 1. Setup environment to allow access to a program
          installed in /opt/foo



          Environment variables exported by the user manager (systemd
          --user instance started in the user@uid.service system
          service) apply to any services started by that manager. In
          particular, this may include services which run user shells.
          For example in the GNOME environment, the graphical terminal
          emulator runs as the gnome-terminal-server.service user
          unit, which in turn runs the user shell, so that shell will
          inherit environment variables exported by the user manager.
          For other instances of the shell, not launched by the user
          manager, the environment they inherit is defined by the

     Page 2                     systemd 247          (printed 5/26/22)

     ENVIRONMENT.D(5)                                 ENVIRONMENT.D(5)

          program that starts them. Hint: in general,
          systemd.service(5) units contain programs launched by
          systemd, and systemd.scope(5) units contain programs
          launched by something else.

          Specifically, for ssh logins, the sshd(8) service builds an
          environment that is a combination of variables forwarded
          from the remote system and defined by sshd, see the
          discussion in ssh(1). A graphical display session will have
          an analogous mechanism to define the environment. Note that
          some managers query the systemd user instance for the
          exported environment and inject this configuration into
          programs they start, using systemctl show-environment or the
          underlying D-Bus call.

          systemd(1), systemd-environment-d-generator(8),

     Page 3                     systemd 247          (printed 5/26/22)