EmacsWiki: Auto Save

By default, Emacs automatically saves your changes to a file intermittently. If anything should happen, you can recover a file with ‘M-x recover-file’. Auto-saving can be turned on globally or on a per-buffer basis with ‘M-x auto-save-mode’.

Placing all files in one directory
Delete auto-save files
Discussion

Placing all files in one directory

By default, auto-save files are stored in the current directory with a file name on the form #file#. If you don’t want to clutter up your file tree with Emacs’ backup files, you can save them to the system’s “temp” directory:

    (setq backup-directory-alist
          `((".*" . ,temporary-file-directory)))
    (setq auto-save-file-name-transforms
          `((".*" ,temporary-file-directory t)))

This will all place all auto-saves and backups in the directory pointed to by temporary-file-directory (e.g., C:/Temp/ on Windows).

Delete auto-save files

To delete all auto-save files in the current directory, use `#’ in Dired to mark the files, then ‘x’ to delete them.
To recursively delete all auto-save files under the current directory, run:

          find -name "#*#" | xargs rm

: If the file names contain whitespace, it is necessary to use one of:

          find -name "#*#" -print0 | xargs -0 rm
          find -name "#*#" -exec rm {} \;

Discussion

How do I turn on auto-saving globally or on a per-buffer basis?

See Manual:Auto Save Control, it should be on by default, but you can turn it off in a buffer with ‘M-x auto-save-mode’. – AaronHawley

Problems with Tramp

Hello, I’m trying to use emacs to edit a file across a locally-mounted network file system. There is a long latency across the connection, so I need to minimize file accesses over the network. However, if I open file “abcd”, emacs creates files like .#abcd, .#abcd.2, etc, in the directory housing the file. This makes things take forever, because each file creation/access in that directory goes across the network. How do I tell emacs to either not create those files, or at the least to create them in /tmp rather than in the same directory as the file? – BayleShanks

See auto-save-file-name-transforms. The default value matches all TRAMP URLs. With a little bit of tweaking, you can add another sexp for your locally-mounted network shares. I use the following incantation to save all my temporary files to another partition, as I occasionally have problems with my data partition.

   (setq auto-save-file-name-transforms
         '(("\\`/[^/]*:\\([^/]*/\\)*\\([^/]*\\)\\'" "/tmp/\\2" t)
          ("\\`/?\\([^/]*/\\)*\\([^/]*\\)\\'" "/usr/local/sacha-backup/\\2" t)))

– SachaChua

Disabling Auto Save

Every time I edit a file and then discard the changes emacs saves a ~/#filename# file. The next time I run emacs it warns me about it and advises me to recover the file. How can I disable this “feature” ?

: That is really two features, “auto save”(1) and “find-file warning messages”(2). Auto-save is easy to disable, just add (setq auto-save-default nil) to your .emacs file. The warning messages are a bit trickier to suppress. There’s an optional parameter in find-file-noselect …

Running save-buffer automatically

All these new-fangled IDEs tout that they automatically save your files for you. I think this would be cool to try out (my c-x c-s muscles get tired sometimes). You can set auto-save-visited-file-name to a non-nil value and emacs auto-save will save your work in the file you are working on instead of a separate file, but then the buffer is considered out of date and you can’t continue editing without an annoying warning message. Is there a way around this? – BryanMurdock

: What about ‘M-x run-with-idle-timer RET SECONDS RET save-buffer RET’? If that’s what you want, then find a way to roll some EmacsLisp to make it work for all your buffers associated with files. Then you can put that in your DotEmacs and smoke it. – AaronHawley

My emacs lisp skills are feeble, but how does this look?

   (defun save-buffer-if-visiting-file (&optional args)
      "Save the current buffer only if it is visiting a file"
      (interactive)
      (if (and (buffer-file-name) (buffer-modified-p))
          (save-buffer args)))

   (add-hook 'auto-save-hook 'save-buffer-if-visiting-file)

It seems to work for me with both regular files and file you visited with tramp. – BryanMurdock

Automatically save your changes after an customizable interval. Can be selectively applied some modes.

http://www.litchie.net/programs/real-auto-save.html

What about to save file when emacs frame loose focus? – VitalieLazu?

To fix the problem of the buffer being considered out of date after an autosave to the file itself, you could put revert-buffer-no-confirm in auto-save-hook, assuming that this runs after the save itself. I accept no responsibility for list work. If this is wrong, someone please delete it. -RyanThompson

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AutoSave

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