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emacs/lisp/env.el
1993-03-28 22:27:23 +00:00

58 lines
2.1 KiB
EmacsLisp

;;; env.el --- functions to manipulate environment variables.
;;; Copyright Free Software Foundation 1991
;; Maintainer: FSF
;; Keywords: processes, unix
;;; This file is part of GNU Emacs.
;;; GNU Emacs 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, or (at your option)
;;; any later version.
;;; GNU Emacs 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 GNU Emacs; see the file COPYING. If not, write to
;;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
;;; Commentary:
;; UNIX processes inherit a list of name-to-string associations from
;; their parents called their `environment'; these are commonly used
;; to control program options. This package permits you to set
;; environment variables to be passed to any sub-process run under Emacs.
;;; Code:
;;;###autoload
(defun setenv (variable &optional value)
"Set the value of the environment variable named VARIABLE to VALUE.
VARIABLE should be a string. VALUE is optional; if not provided or is
`nil', the environment variable VARIABLE will be removed.
This function works by modifying `process-environment'."
(interactive "sSet environment variable: \nsSet %s to value: ")
(if (string-match "=" variable)
(error "Environment variable name `%s' contains `='" variable)
(let ((pattern (concat "\\`" (regexp-quote (concat variable "="))))
(scan process-environment))
(while scan
(cond
((string-match pattern (car scan))
(if (eq nil value)
(setq process-environment (delq (car scan) process-environment))
(setcar scan (concat variable "=" value)))
(setq scan nil))
((null (setq scan (cdr scan)))
(setq process-environment
(cons (concat variable "=" value) process-environment))))))))
(provide 'env)
;;; env.el ends here