When I execute find-grep command in emacs, I got find . -type f -exec grep -nH -e {} +, since I'm using fish shell as the default shell, to make this command work I have to execute find . -type f -exec grep -nH -e \{\} +.
I tried to modify the emacs source code, below are my changes:
/usr/share/emacs/24.4/lisp/ldefs-boot.el line 12669: If `exec-plus' use `find -exec \{\} +'.
/usr/share/emacs/24.4/lisp/loaddefs.el line 12669: If `exec-plus' use `find -exec \{\} +'.
But it doesn't make any sense, when I execute find-grep still shows find . -type f -exec grep -nH -e {} +. Can anyone tell me where I am doing wrong or how should I figure out this?
The text you changed does not look like executable code. Probably you just changed a doc string (actually, a bit of googling reveals that this is in the documentation string for grep-find-use-xargs). But Emacs is eminently customizable; all you have to do is to set the value of grep-find-template to something which is more suitable for you personally, in your own .emacs/init.el or similar.
(setq grep-find-template
"find <D> <X> -type f <F> -exec grep <C> -nH -e <R> \\{\\} +")
See the manual for further documentation and, of course, the built-in documentation (ctrl-h v grep-find-template RET).
The actual source code is in http://git.savannah.gnu.org/cgit/emacs.git/tree/lisp/progmodes/grep.el#n174 but you really, really, really do not want to edit the source code. The user-level customizability without code changes is one of the foundational designs of Emacs. Learn to use this facility.