Direct emacs that open file from the pwd from shell buffer

Question

I use shell mode, often. I use the c-xc-f. Most of the time, the start directory for looking for file, correspond to the PWD of the emacs shell buffer. Can i set that it is always the case/or reset it?

Answer 1

If you want the shell to always start from a specific directory, you can use the shell-mode-hook. Code stored in a mode hook is executed after the mode is loaded.

We want to send a command to change the directory once the shell process has started. There isn't a stock function to send commands to a shell process. However, there's a great StackOverflow response which provides one¹:

(defun sh-send-command (command)
  "Send COMMAND to current shell process.  Create shell process
if none exists."
  (let ((proc (get-process "shell"))
        pbuf)
    (unless proc
      (let ((currbuff (current-buffer)))
        (shell)
        (switch-to-buffer currbuff)
        (setq proc (get-process "shell"))
        ))
    (setq pbuff (process-buffer proc))
    (setq command-and-go (concat command "\n"))
    (with-current-buffer pbuff
      (goto-char (process-mark proc))
      (insert command-and-go)
      (move-marker (process-mark proc) (point))
      )
    (process-send-string proc command-and-go)
    ))

This can be used in the shell-mode-hook like:

(add-hook 'shell-mode-hook (lambda () (interactive) (sh-send-command "cd /path/to/start/at")))

This creates an anonymous function which calls the shell command cd to change directory to the given path. Note that you'll need to quote a path containing spaces. To do this, escape the inner quotes using a backslash: \".

If you're interested in setting a default directory across all of Emacs, and not just shell, you might be interested in this SO question: set a global default directory.

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¹If you like this function, give user VitoshKa an upvote!