CODEWITHSUNDEEP
bashemacselispzsh
ysakamoto
ysakamoto

Reputation: 2532

source from within emacs to load environmental variables

I have different environmental variables in different files, and usually use source to load/unload these. Now I want to change my environmental variables while using emacs. Is there any way to sourcefrom within emacs?

Upvotes: 0

Views: 816

Answers (1)

François Févotte
François Févotte

Reputation: 20258

In order to change the environment of Emacs itself (which will be inherited by all commands run by it, like compilation commands or shells), I use the following setup:

  1. in the emacs init file, the following snippets defines (and calls) a function which starts the server and exports its name in the EMACS_SERVER environment variable. 

    (defun my/server-start ()
  "Start an emacs server using an automatically generated name.

If an emacs server is already running, it is restarted.
The EMACS_SERVER environment variable is set, so that child processes
can know which emacs server to contact."

  (if (and (boundp 'server-process)
           server-process
           (memq (process-status server-process) '(connect listen open run)))
      ;; There is already an instance running; just restart it
      (server-start)

    ;; Start a new server
    (let ((i       0)
          (max-try 100)
          (ok      nil))
      (while (and (< i max-try)
                  (not ok))
        (setq server-name (format "server%d" i))
        (setq i (1+ i))
        (unless (server-running-p server-name)
          (setq ok t)))
      (if (>= i max-try)
          (display-warning 'my/server-start
                           "Could not find any unused server name."
                           :warning)
        (message "Starting server with name %s." server-name)
        (server-start))))
  (setenv "EMACS_SERVER" server-name))

(my/server-start)

  2. in my ~/.bashrc file, the following function allows sourcing a shell script and exporting the resulting environment to the emacs server referenced by $EMACS_SERVER:

    E-source () 
{ 
    ( if [ -n "$1" ]; then
        source "$1";
    fi;
    export | perl -pn -e 's/^declare -x //;' -e 's/([^=]+)=(.*)$/(setenv "$1" $2)/' | while read line; do
        emacsclient -s ${EMACS_SERVER} -e "$line";
    done )
}

  3. all this being set up, when I want to develop in a project, I open a shell/term/multi-term buffer and while in it, I run

    E-source my-env.sh

    before running the compilation commands I need for developping in this particular project.

All this is somewhat complex, but I found it less error-prone than endlessly prefixing all compilation commands with source my-env.sh, and also sourcing the environment in all shell/term/multi-term buffers.

Upvotes: 1

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