Ubuntu – How to set environment variables in an Emacs session launched from Gnome Panel

bashemacsgnome-panel

My .bash_env file sets several environment variables, including PATH and EMAIL, but in an Emacs session launched from the Gnome Panel (command: "/usr/bin/emacs23 %F") these variables do not have the expected values. I've run into this problem before (see this blog post). I fixed it then by sourcing .bash_env in my .xsession file. Obviously, this is no longer working.

The variables are set properly if I manually launch Emacs from a terminal. Oddly, they aren't set if I change the panel launcher to execute Emacs in a terminal (I would think this would start Bash before starting Emacs).

How can I make sure the regular Bash environment is set up for the Emacs session?

Best Answer

Set the environment variables in ~/.profile (and source ~/.profile from ~/.xsession if you use a .xsession). That way they will be available everywhere, because they'll be set when you log in.

~/.bash_env is not the right place for environment variables (despite the name) . (Despite its existence (that's $BASH_ENV, right?) I've yet to find a good use for it.)

When you run Emacs in a terminal, it is a subprocess of the terminal emulator. There would be no reason to have a shell in between.

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Ubuntu – How to add environment variables

To set variable only for current shell:

VARNAME="my value"

To set it for current shell and all processes started from current shell:

export VARNAME="my value"      # shorter, less portable version

To set it permanently for all future bash sessions add such line to your .bashrc file in your $HOME directory.

To set it permanently, and system wide (all users, all processes) add set variable in /etc/environment:

sudo -H gedit /etc/environment

This file only accepts variable assignments like:

VARNAME="my value"

Do not use the export keyword here.

You need to logout from current user and login again so environment variables changes take place.

Ubuntu – Difference between launching an application from a keyboard shortcut vs the terminal

~/.bashrc is usually read for secondary interactive shells after you log in. If you want to initialise your parameters on login the use ~/.profile instead. To apply you parameters system-wide use /etc/profile. It's the first file read by bash.

To make things clearer I think I'd explain a bit more.

When you login, your login shell reads first the global /etc/profile, then ~/.profile and parameters/variables mentioned there are initialised. However you don't see this shell as terminal because the X-window system GUI is running.
After login when you open a secondary terminal/terminal-emulator e.g. gnome-terminal ~/.bashrc is read and and the parameters/variables declared in it are available to the secondary terminal only. Note that this secondary terminal is a child process of your login shell.
When you launch an application from menu, it's executed as a child process of your login shell and it inherits the parameters from it's ancestor process. But .bashrc was not available for the main login shell; so it's not available for applications too. So anything in .bashrc won't be available for those applications if run from menu. But when you open a gnome-terminal and executes command from there, applications are launched as children of gnome-terminal and inherits .bashrc's parameters from it.

Best Answer

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Ubuntu – How to add environment variables

Ubuntu – Difference between launching an application from a keyboard shortcut vs the terminal

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