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I am using Ubuntu Desktop 14.04, and as such, I am using the non-login shell. When I open the GUI terminal, first the non-login shell sessions read the following startup files:

/etc/bash.bashrc
~/.bashrc

The non-login shells inherit the environment from the parent process, which is a login shell, so the session also reads the following startup files:

/etc/profile
~/.bash_profile

However, I cannot find the $PATH for system-wide paths like /bin, /sbin, /usr/bin, /usr/sbin, set in any of these files. Where is the $PATH set for these directories?

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The (default) system wide PATH is set in the /etc/environment file.

$ cat /etc/environment 
PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games"

It is basically the place to save the global environment variables.

  • +1, however do you happen to know if $PATH it's inherited by the parent login shell or if it's reloaded by each bash instance? – kos Jun 10 '15 at 4:43
  • @kos All child processes inherit the environment from parent shell unless of course being run in a modified environment.. – heemayl Jun 10 '15 at 10:02
  • I notice that the shell does not seem to expand the $HOME variable. For instance, adding $HOME/.composer/vendor/bin to the PATH in /etc/environment does not enable binaries in this directory to be executed without a path prefix. Using ~/.composer/vendor/bin does not work either. I'm finding it necessary to add the absolute path, e.g.: /home/vagrant/.composer/vendor/bin. This seems related (though doesn't explain this behavior): askubuntu.com/questions/402353/… – Ben Johnson Jan 26 '18 at 1:40
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    @BenJohnson That's simply because /etc/environment (and ~/.pam/environment) is read by pam_env PAM module, not shell or anything else that understands shell/environment variables; same goes for ~ expansion. So, you need to use absolute path there. – heemayl Jan 26 '18 at 14:31

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