Emacs: Turn Off Auto Backup; Set Backups into a Directory; How to Delete Backup Files

How to make emacs stop creating “backup~” files or “#autosave#” files?

Put the following in your emacs init file.

(setq make-backup-files nil) ; stop creating backup~ files
(setq auto-save-default nil) ; stop creating #autosave# files

How to set emacs so that all backups are placed in one place?

Put the following in your emacs init:

;; backup in one place. flat, no tree structure
(setq backup-directory-alist '(("" . "~/.emacs.d/emacs-backup")))

This will create backup files flat in the given dir, and the backup file names will have “!” characters in place of the directory separator.

For example:

• file /A/B/web/xyz/myfile.txt
• backup root dir /A/B/.emacs.d/emacs-backup
• backup at /A/B/.emacs.d/emacs-backup/A!B!web!emacs!myfile.txt~

If you use long file names or many nested dirs, this scheme will reach file name length limit quickly. (Mac and Windows allow 255 chars for file name.)

How to set emacs so backups in one place with tree structure?

Put the following in your emacs init file:

;; make backup to a designated dir, mirroring the full path

(defun my-backup-file-name (fpath)
  "Return a new file path of a given file path.
If the new path's directories does not exist, create them."
  (let* (
        (backupRootDir "~/.emacs.d/emacs-backup/")
        (filePath (replace-regexp-in-string "[A-Za-z]:" "" fpath )) ; remove Windows driver letter in path, for example, “C:”
        (backupFilePath (replace-regexp-in-string "//" "/" (concat backupRootDir filePath "~") ))
        )
    (make-directory (file-name-directory backupFilePath) (file-name-directory backupFilePath))
    backupFilePath
  )
)

(setq make-backup-file-name-function 'my-backup-file-name)

The above will mirror tree structure to the backup dir.

For example:

• file /A/B/web/xyz/myfile.txt
• backup root dir /A/B/.emacs.d/emacs-backup/
• backup at /A/B/.emacs.d/emacs-backup/A/B/web/xyz/myfile.txt~