exec-path-from-shell

A GNU Emacs library to ensure environment variables inside Emacs look the same as in the user's shell.

Motivation

Ever find that a command works in your shell, but not in Emacs?

This happens a lot on OS X, where an Emacs instance started from the GUI inherits a default set of environment variables.

This library solves this problem by copying important environment variables from the user's shell: it works by asking your shell to print out the variables of interest, then copying them into the Emacs environment.

Compatibility

At a minimum, this package assumes that your shell is at least UNIX-y: if (getenv "SHELL") evaluates to something like ".../cmdproxy.exe", this package probably isn't for you.

Further, if you use a non-POSIX-standard shell such as tcsh or fish, your shell will be asked to execute sh as a subshell in order to print out the variables in a format which can be reliably parsed. sh must be a POSIX-compliant shell in this case.

Note that shell variables which have not been exported as environment variables (e.g. using the "export" keyword) may not be visible to `exec-path-from-shell'.

Installation

Installable packages are available via MELPA. Alternatively, download the latest release or clone the repository, and install exec-path-from-shell.el with M-x package-install-file.

Usage

Add the following to your init.el (after calling package-initialize):

(when (memq window-system '(mac ns x))
  (exec-path-from-shell-initialize))

This sets $MANPATH, $PATH and exec-path from your shell, but only on OS X and Linux.

You can copy values of other environment variables by customizing exec-path-from-shell-variables before invoking exec-path-from-shell-initialize, or by calling exec-path-from-shell-copy-env, e.g.:

(exec-path-from-shell-copy-env "PYTHONPATH")

This function may also be called interactively.

Note that your shell will inherit Emacs's environment variables when it is run -- to avoid surprises your config files should therefore set the environment variables to their exact desired final values, i.e. don't do this:

export PATH=/usr/local/bin:$PATH

but instead do this:

export PATH=/usr/local/bin:/usr/bin:/bin

Further help

C-h f exec-path-from-shell-initialize
C-h f exec-path-from-shell-copy-env

License

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.