How to reload /etc/environment without rebooting?

Question

/etc/environment is officially the correct place for system wide environment variables. But how can I reload the assignments in this file without rebooting or relogging?

Interestingly enough google does not help me here, aside from the dozens of blog posts suggesting to use

source /etc/environment

which obviously will never work because /etc/environment is a list of assigments (one per line) and not an executable script (hence the missing export commands in /etc/environment ...).

Answer 1

One thing you are mistaken about is that /etc/environment requires a reboot to reload. This is incorrect. The only time the file is read is on login, when the PAM stack is activated – specifically pam_env.so, which reads the file.

Logging out and back in would apply the changes – and in fact you must do this if you want all your processes to receive the new environment. All other "solutions"² will only apply the environment to the single shell process, but not to anything you launch through the GUI including new terminal windows.¹

If you're fine with that, though – the lack of export commands can be compensated for with set -a and set +a. However, it still remains a poor way, as the file doesn't use quoting either. But this should work fine:

while read -r env; do export "$env"; done

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¹ GNOME Session Manager provides a way to change its own environment, but only during the Initialization phase:

$ gdbus call -e -d org.gnome.SessionManager -o /org/gnome/SessionManager \
    -m org.gnome.SessionManager.Setenv "foo" "bar"
Error: GDBus.Error:org.gnome.SessionManager.NotInInitialization: Setenv
    interface is only available during the Initialization phase

² gdb is not a solution (unless you are grawity).