How do I reload a file in a buffer?

Question

I usually work on files which are updated in the file system via version control. What's a quick way to reload a file without having to C-x C-f the file again and getting asked if I want to reload it?

Answer 1

M-x revert-buffer will do exactly what you want. It will still ask for confirmation.

Another option (my favorite) is the below function:

;; Source: https://www.emacswiki.org/emacs/misc-cmds.el
(defun revert-buffer-no-confirm ()
    "Revert buffer without confirmation."
    (interactive)
    (revert-buffer :ignore-auto :noconfirm))

Answer 2

There is also auto-revert-mode which does it automatically and gives you feedback.

From the doc string:

auto-revert-mode is an interactive autoloaded compiled Lisp function
in `autorevert.el'.

(auto-revert-mode &optional ARG)

Toggle reverting buffer when the file changes (Auto Revert mode).
With a prefix argument ARG, enable Auto Revert mode if ARG is
positive, and disable it otherwise.  If called from Lisp, enable
the mode if ARG is omitted or nil.

Auto Revert mode is a minor mode that affects only the current
buffer.  When enabled, it reverts the buffer when the file on
disk changes.

Use `global-auto-revert-mode' to automatically revert all buffers.
Use `auto-revert-tail-mode' if you know that the file will only grow
without being changed in the part that is already in the buffer.

Answer 3

Another option, which I use, is find-alternate-file bound to C-x C-v. This opens a file reusing your current buffer.

By default, it points to the file you're currently on, so you can just type C-x C-v RET to reload your file. It won't prompt unless your buffer has unsaved data.

Some non-text modes like image-mode (used for rendering pictures, pdfs, svgs...etc) and dired have revert-buffer bound to g for faster access.

Answer 4

Emacs calls this reverting.

You can revert the current file with M-x revert-buffer. This prompts for confirmation whether the file has been modified or not, except for files that match patterns listed in the variable revert-without-query (see the manual for details). Another occasional annoyance of revert-buffer is that it resets the file mode to the default.

I use the following function to revert a bunch of files, given by name. If a file isn't opened in some buffer, it is ignored.

(defun revert-files (&rest files)
  "Reload all specified files from disk.
Only files that are currently visited in some buffer are reverted.
Do not ask confirmation unless the buffer is modified."
  (save-excursion
    (let ((revert-without-query '("")))
      (dolist (file-name files)
        (message "Considering whether to revert file %s" file-name)
        (let ((buf (find-buffer-visiting file-name)))
          (when buf
            (message "Reverting file in buffer %s" (buffer-name buf))
            (set-buffer buf)
        (revert-buffer t nil t)))))))

A typical use case for this function is after updating files from version control. Use emacsclient to call revert-files on all the files that have been updated, or (this is easier, and only slightly slower) on all the files concerned by the update. I call the following shell script, passing it the files as arguments:

#! /bin/sh
# Similar to gnuclient, but call `revert-files' on the files.
files=

## Find a way to convert a path to absolute. Bizarre OSes such as Windows
## require special cases. We also try to detect non-filenames such as URIs.
case `uname -s` in
  CYGWIN*)
    absolute_path () {
      cygpath -a -w -- "$1"
    };;
  *)
    wd="`pwd -P 2>/dev/null || pwd`"
    absolute_path () {
      case "$1" in
        /*) printf '%s' "$1";; # ordinary absolute path
        *:/*)
          if expr "z$1" : 'z[0-9A-Z_a-z][-.0-9@A-Z_a-z]*:/.*'; then
            printf '%s' "$1" # URI or machine:/some/path
          else
            printf '%s' "$wd/$1" # default to a relative path
          fi;;
        *) printf '%s' "$wd/$1";; # default to a relative path
      esac
    };;
esac

for x; do
  files="$files \"`absolute_path "$x" | sed 's/[\\\\\\\"]/\\\\&/g'`\""
done
exec emacsclient -e "(revert-files$files)"

Usage example:

svn update
find -name .svn -prune -o -type f -exec emacsclient-revert {} +

Answer 5

revert-buffer is there. But I like to have some feedback.

I have the following in my .emacs.

(global-set-key (kbd "C-c r") (lambda ()
                                (interactive)
                                (revert-buffer t t t)
                                (message "buffer is reverted")))

Answer 6

you can also enable global-auto-revert-mode as shown below

(global-auto-revert-mode 1)

this is helpful when you do a lot of checks of your js files with auto-fix mode enabled, like in jssc.

Answer 7

You can use find-alternate-file, which is bound to C-x C-v by default, and just simply type RET at the prompt to reload the file.

Answer 8

For spacemacs users: SPC b R (spacemacs/safe-revert-buffer).

For skipping confirmation, other answers already cover that, though I agree with others that it's probably not a good idea to bind that to a key.

Answer 9

Magit manages file reversions for you automatically, thus solving your core problem. You also benefit from its other features.

Here are the docs for tweaking the settings you're interested in:

If you stick with Magit, also be sure to enable all 3 global WIP modes (Work In Progress) to avoid losing work.

You can thus perform version-control actions inside Emacs with Magit and avoid your original problem altogether.

Answer 10

It seems there is a built-in function named revert-buffer-quick which does the trick (source). It checks if you have unsaved modification on the buffer, if there is any, it asks for confirmation, otherwise it will revert (i.e. reload) the file. The default keybinding in vanilla emacs is C-x x g which is long, so I have bound it to F5 as well:

(global-set-key (kbd "<f5>") 'revert-buffer-quick)