To make bash parse a file when invoked as a non-interactive shell, you need to set the environment variable
BASH_ENV to point to that file. From
man bash (section on INVOCATION):
When bash is started non-interactively, to run a shell script, for
example, it looks for the variable BASH_ENV in the environment, expands
its value if it appears there, and uses the expanded value as the name
of a file to read and execute. Bash behaves as if the following com‐
mand were executed:
if [ -n "$BASH_ENV" ]; then . "$BASH_ENV"; fi
but the value of the PATH variable is not used to search for the file‐
So where to set
If you want a variable to be available to the environment system-wide, a good place to put it is
/etc/environment. This file is specifically made for system-wide environment variable settings. It is not parsed by the shell but by the PAM module
pam_env, so you can not use shell syntax or variable expansion within, but only simple assignments of the following type:
Changes will take effect at the next login/authentication, so switch to a new tty console or logout and re-login to your session.
On a standard desktop system, this should work for all types of authenticated sessions using PAM, including console logins, ssh and display managers, but also daemons such as atd and cron. If everything works as expected, then you are done and there is no need to read on.
However, mistakes do occasionally sneak into the PAM configuration files of some programs/distributions, so if
/etc/environment is not parsed by a certain type of program, make sure that the necessary PAM module is loaded in the PAM configuration file for that program in
session required pam_env.so readenv=1
readenv flag which turns reading of the config file on/off should not actually be needed, since it is set to on (1) by default - but it doesn't hurt to make sure either.)
If you are working on a system that does not provide
pam_env, then the best alternative that comes to my mind would be write a simple init script (or service unit file on systemd) that parses a custom config file (such as
/etc/default/environment) at boot.