(shell-snarf-envar, shell-copy-environment-variable): New functions.

diff --git a/lisp/shell.el b/lisp/shell.el
index 9fbfd61e226941fc8db827e597491b51d14148c9..c28f1649eb69ad5092112f7358c687ed8c122d80 100644 (file)
--- a/lisp/shell.el
+++ b/lisp/shell.el
@@ -731,6 +731,37 @@ command again."
        (setq ds (cdr ds))))
     (message "%s" msg)))
 \f
+;; This was mostly copied from shell-resync-dirs.
+(defun shell-snarf-envar (var)
+  "Return as a string the shell's value of environment variable VAR."
+  (let* ((cmd (format "printenv '%s'\n" var))
+        (proc (get-buffer-process (current-buffer)))
+        (pmark (process-mark proc)))
+    (goto-char pmark)
+    (insert cmd)
+    (sit-for 0)                                ; force redisplay
+    (comint-send-string proc cmd)
+    (set-marker pmark (point))
+    (let ((pt (point)))                        ; wait for 1 line
+      ;; This extra newline prevents the user's pending input from spoofing us.
+      (insert "\n") (backward-char 1)
+      (while (not (looking-at ".+\n"))
+       (accept-process-output proc)
+       (goto-char pt)))
+    (goto-char pmark) (delete-char 1)  ; remove the extra newline
+    (buffer-substring (match-beginning 0) (1- (match-end 0)))))
+
+(defun shell-copy-environment-variable (variable)
+  "Copy the environment variable VARIABLE from the subshell to Emacs.
+This command reads the value of the specified environment variable
+in the shell, and sets the same environment variable in Emacs
+\(what `getenv' in Emacvs would return) to that value.
+That value will affect any new subprocesses that you subsequently start
+from Emacs."
+  (interactive (list (read-envvar-name "\
+Copy Shell environment variable to Emacs: ")))
+  (setenv variable (shell-snarf-envar variable)))
+\f
 (defun shell-forward-command (&optional arg)
   "Move forward across ARG shell command(s).  Does not cross lines.
 See `shell-command-regexp'."