diff --git a/lisp/progmodes/grep.el b/lisp/progmodes/grep.el index 9962945..763f906 100644 --- a/lisp/progmodes/grep.el +++ b/lisp/progmodes/grep.el @@ -77,11 +77,10 @@ in grep buffers, so if you have globally disabled font-lock-mode, you will not get highlighting. This option sets the environment variable GREP_COLORS to specify -markers for highlighting and GREP_OPTIONS to add the --color -option in front of any explicit grep options before starting -the grep. +markers for highlighting and adds the --color option in front of +any explicit grep options before starting the grep. -When this option is `auto', grep uses `--color=auto' to highlight +When this option is `auto', grep uses `--color' to highlight matches only when it outputs to a terminal (when `grep' is the last command in the pipe), thus avoiding the use of any potentially-harmful escape sequences when standard output goes to a file or pipe. @@ -97,7 +96,7 @@ To change the default value, use Customize or call the function :type '(choice (const :tag "Do not highlight matches with grep markers" nil) (const :tag "Highlight matches with grep markers" t) (const :tag "Use --color=always" always) - (const :tag "Use --color=auto" auto) + (const :tag "Use --color" auto) (other :tag "Not Set" auto-detect)) :set 'grep-apply-setting :version "22.1" @@ -467,10 +466,6 @@ Set up `compilation-exit-message-function' and run `grep-setup-hook'." ;; `setenv' modifies `process-environment' let-bound in `compilation-start' ;; Any TERM except "dumb" allows GNU grep to use `--color=auto' (setenv "TERM" "emacs-grep") - (setenv "GREP_OPTIONS" - (concat (getenv "GREP_OPTIONS") - " --color=" (if (eq grep-highlight-matches 'always) - "always" "auto"))) ;; GREP_COLOR is used in GNU grep 2.5.1, but deprecated in later versions (setenv "GREP_COLOR" "01;31") ;; GREP_COLORS is used in GNU grep 2.5.2 and later versions @@ -570,7 +565,13 @@ This function is called from `compilation-filter-hook'." (unless (and grep-command grep-find-command grep-template grep-find-template) (let ((grep-options - (concat (if grep-use-null-device "-n" "-nH") + (concat (and grep-highlight-matches + (grep-probe grep-program + `(nil nil nil "--color" "x" ,null-device) + nil 1) + (if (eq grep-highlight-matches 'always) + "--color=always " "--color ")) + (if grep-use-null-device "-n" "-nH") (if (grep-probe grep-program `(nil nil nil "-e" "foo" ,null-device) nil 1)