:PROPERTIES:
:ID:       3c67e623-c269-4c9b-9bdf-4ad677d46a35
:END:
#+title: systemd environment directives
#+date: 2021-08-07 19:58:29 +08:00
#+date_modified: 2022-04-16 20:19:15 +08:00
#+language: en


systemd enables setting the environment through environment directives.
For some, this is a nice shell-agnostic way of setting environment variables and could replace setting through shell profiles (i.e., =.bashrc=, =.profile=).

It needs a =*.conf= file in one of the load paths (seen from the =environment.d.5= manual page).
Just like how [[id:c7edff80-6dea-47fc-8ecd-e43b5ab8fb1e][systemd at user-level]], you can set it at user-level by placing them in certain user-level load paths (e.g., =$XDG_CONFIG_HOME/environment.d=).

Keep in mind it does not use the shell directly and instead makes use of shell-like syntax.
The syntax takes variable substitutions and parameter expansion seen from [[id:dd9d3ffa-03ff-42a1-8c5d-55dc9fcc70fe][GNU Bash]].

The following code block is an example of setting Nix-related environment variables to enable desktop integrations.

#+begin_src ini
# Enable desktop integration with Nix-installed applications.
NIX_PATH=$HOME/.nix-defexpr/channels${NIX_PATH:+:}$NIX_PATH
PATH=${PATH:+$PATH:}$HOME/.nix-profile/bin
XDG_DATA_DIRS=${XDG_DATA_DIRS:+$XDG_DATA_DIRS:}$HOME/.nix-profile/share/
#+end_src