run a shell command from a specific directory in emacs

Question

How do I execute a shell command (eg, git gui) from a specific directory? I'd prefer a cross-platform approach that doesn't depend shell operators like && or ; because I need this to run on Windows and unix. (For example, calling cd /path/to/dir && git gui won't work on Windows because && is not valid.)

I tried:

(async-shell-command (concat "cd \""
  (replace-regexp-in-string 
    "/" "\\\\" (file-name-directory (buffer-file-name))) "\" ; git gui"))

That fails because for whatever reason the shell thinks ; git gui is part of the path, and it reports: The system cannot find the path specified.

So, I'd rather not deal with shell quirks and I'm hoping there's an elisp function that sets the directory for shell-command or async-shell-command. I tried:

 (shell-process-pushd (file-name-directory (buffer-file-name)))
 (shell-command "git gui")
 (shell-process-popd nil)

That had no effect: git gui always opens in my home directory. (Also, shell-process-pushd/popd are not documented.)

This also doesn't work:

(start-process "gitgui" nil "git" "gui")

Neither does this:

(let '(bufdir (file-name-directory (buffer-file-name))) 
       (with-temp-buffer
         (print bufdir)
         (cd bufdir)
         (shell-command "git gui")))

Answer 1

(shell-command) does use the the buffer's default-directory, which means there is no reason to cd to the buffer's directory.

The problem in my case was that I was mistakenly running git gui on a buffer that didn't have an associated .git/ directory.

Answer 2

Are you sure you're using the trailing slash to indicate directory name in emacs-lisp?

(let ((default-directory "~/.emacs.d"))
  (shell-command-to-string "echo $PWD"))
        ;;; ⇒ "/Users/me"

(let ((default-directory "~/.emacs.d/"))
  (shell-command-to-string "echo $PWD"))
        ;;; ⇒ "/Users/me/.emacs.d"

Answer 3

Try this:

(let ((default-directory "~/.emacs.d/")) (shell-command "ls"))