ENVIRONMENT.D(5) environment.d ENVIRONMENT.D(5)
NAME
environment.d - Definition of user service environment
SYNOPSIS
~/.config/environment.d/*.conf
/etc/environment.d/*.conf
/run/environment.d/*.conf
/usr/lib/environment.d/*.conf
/etc/environment
DESCRIPTION
Configuration files in the environment.d/ directories contain lists of
environment variable assignments passed to 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 variables.
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 DIRECTORIES AND PRECEDENCE
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 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.
CONFIGURATION FORMAT
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
Example 1. Setup environment to allow access to a program installed in
/opt/foo
/etc/environment.d/60-foo.conf:
FOO_DEBUG=force-software-gl,log-verbose
PATH=/opt/foo/bin:$PATH
LD_LIBRARY_PATH=/opt/foo/lib${LD_LIBRARY_PATH:+:$LD_LIBRARY_PATH}
XDG_DATA_DIRS=/opt/foo/share:${XDG_DATA_DIRS:-/usr/local/share/:/usr/share/}
APPLICABILITY
Environment variables exported by the user service manager (systemd
--user instance started in the user@uid.service system service) are
passed to any services started by that service 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 service manager, the environment they inherit is defined by the
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.
Note that these files do not affect the environment block of the
service manager itself, but exclusively the environment blocks passed
to the services it manages. Environment variables set that way thus
cannot be used to influence behaviour of the service manager. In order
to make changes to the service manager's environment block the
environment must be modified before the user's service manager is
invoked, for example from the system service manager or via a PAM
module.
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.
SEE ALSO
systemd(1), systemd-environment-d-generator(8), systemd.environment-
generator(7)
systemd 252 ENVIRONMENT.D(5)
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