Question

I need to use my $PATH in Emacs to run some commands. How can I make Emacs use it? I installed Emacs from Ubuntu repositories.

Answer 1

Here’s a trick I use to ensure my GUI Emacs always sees the same $PATH that I get inside a shell:

(defun set-exec-path-from-shell-PATH ()
  (let ((path-from-shell (replace-regexp-in-string
                          "[ \t\n]*$"
                          ""
                          (shell-command-to-string "$SHELL --login -i -c 'echo $PATH'"))))
    (setenv "PATH" path-from-shell)
    (setq eshell-path-env path-from-shell) ; for eshell users
    (setq exec-path (split-string path-from-shell path-separator))))

(when window-system (set-exec-path-from-shell-PATH))

Specifically, on OS X, a graphical Emacs will not pick up the user’s shell’s definition of $PATH, so this trick helps me on that platform.

Update: this code has now been published as an elisp library called exec-path-from-shell and installable packages are available in MELPA.