How do I control how Emacs makes backup files

Question

Emacs puts backup files named foo  everywhere and I don t like having to remember to delete them   Also  if I edit a file that has a hard link somewhere else in the file system  the hard link points to the backup when I m done editing  and that s confusing and awful   How can I either eliminate these backup files  or have them go somewhere other than the same directory

User · Answer

Another way of configuring backup options is via the Customize interface. Enter:

M-x customize-group

And then at the Customize group: prompt enter backup.

If you scroll to the bottom of the buffer you'll see Backup Directory Alist. Click Show Value and set the first entry of the list as follows:

Regexp matching filename: .*
Backup directory name: /path/to/your/backup/dir

Alternatively, you can turn backups off my setting Make Backup Files to off.

If you don't want Emacs to automatically edit your .emacs file you'll want to set up a customisations file.

User · Answer

You can disable them altogether by   setq make-backup-files nil

User · Answer

If you ve ever been saved by an Emacs backup file  you probably want more of them  not less of them   It is annoying that they go in the same directory as the file you re editing  but that is easy to change   You can make all backup files go into a directory by putting something like the following in your  emacs    setq backup-directory-alist              saves       There are a number of arcane details associated with how Emacs might create your backup files   Should it rename the original and write out the edited buffer   What if the original is linked  In general  the safest but slowest bet is to always make backups by copying    setq backup-by-copying t    If that s too slow for some reason you might also have a look at backup-by-copying-when-linked   Since your backups are all in their own place now  you might want more of them  rather than less of them   Have a look at the Emacs documentation for these variables  with C-h v     setq delete-old-versions t   kept-new-versions 6   kept-old-versions 2   version-control t    Finally  if you absolutely must have no backup files    setq make-backup-files nil    It makes me sick to think of it though

User · Answer

The accepted answer is good  but it can be greatly improved by additionally backing up on every save and backing up versioned files   First  basic settings as described in the accepted answer    setq version-control t        Use version numbers for backups        kept-new-versions 10     Number of newest versions to keep        kept-old-versions 0      Number of oldest versions to keep        delete-old-versions t    Don t ask to delete excess backup versions        backup-by-copying t      Copy all files  don t rename them    Next  also backup versioned files  which Emacs does not do by default  you don t commit on every save  right      setq vc-make-backup-files t    Finally  make a backup on each save  not just the first  We make two kinds of backups    per-session backups  once on the first save of the buffer in each Emacs session  These simulate Emac s default backup behavior  per-save backups  once on every save  Emacs does not do this by default  but it s very useful if you leave Emacs running for a long time    The backups go in different places and Emacs creates the backup dirs automatically if they don t exist      Default and per-save backups go here   setq backup-directory-alist             emacs d backup per-save       defun force-backup-of-buffer         Make a special  per session  backup at the first save of each      emacs session     when  not buffer-backed-up         Override the default parameters for per-session backups       let   backup-directory-alist             emacs d backup per-session                kept-new-versions 3          backup-buffer         Make a  per save  backup on each save   The first save results in      both a per-session and a per-save backup  to keep the numbering      of per-save backups consistent     let   buffer-backed-up nil        backup-buffer      add-hook  before-save-hook   force-backup-of-buffer    I became very interested in this topic after I wrote   lt  instead of    in my Makefile  about three hours after my previous commit  P  The above is based on an Emacs Wiki page I heavily edited

User · Answer

Emacs backup auto-save files can be very helpful  But these features are confusing    Backup files  Backup files have tildes    or  9   at the end and shall be written to the user home directory  When make-backup-files is non-nil Emacs automatically creates a backup of the original file the first time the file is saved from a buffer  If you re editing a new file Emacs will create a backup the second time you save the file    No matter how many times you save the file the backup remains unchanged  If you kill the buffer and then visit the file again  or the next time you start a new Emacs session  a new backup file will be made   The new backup reflects the file s content after reopened  or at the start of editing sessions  But an existing backup is never touched again  Therefore I find it useful to created numbered backups  see the configuration below     To create backups explicitly use save-buffer  C-x C-s  with prefix arguments    diff-backup and dired-diff-backup compares a file with its backup or vice versa  But there is no function to restore backup files  For example  under Windows  to restore a backup file  C  Users USERNAME  emacs d backups  drive c Users USERNAME  emacs el  7    it has to be manually copied as  C  Users USERNAME  emacs el   Auto-save files  Auto-save files use hashmarks     and shall be written locally within the project directory  along with the actual files   The reason is that auto-save files are just temporary files that Emacs creates until a file is saved again  like with hurrying obedience       Before the user presses C-x C-s  save-buffer  to save a file Emacs auto-saves files - based on counting keystrokes  auto-save-interval  or when you stop typing  auto-save-timeout    Emacs also auto-saves whenever it crashes  including killing the Emacs job with a shell command     When the user saves the file  the auto-saved version is deleted  But when the user exits the file without saving it  Emacs or the X session crashes  the auto-saved files still exist    Use revert-buffer or recover-file to restore auto-save files  Note that Emacs records interrupted sessions for later recovery in files named    emacs d auto-save-list  The recover-session function will use this information   The preferred method to recover from an auto-saved filed is M-x revert-buffer RET  Emacs will ask either  Buffer has been auto-saved recently  Revert from auto-save file   or  Revert buffer from file FILENAME    In case of the latter there is no auto-save file  For example  because you have saved before typing another auto-save-intervall keystrokes  in which case Emacs had deleted the auto-save file   Auto-save is nowadays disabled by default because it can slow down editing when connected to a slow machine  and because many files contain sensitive data   Configuration  Here is a configuration that IMHO works best    defvar --backup-directory  concat user-emacs-directory  backups     if  not  file-exists-p --backup-directory            make-directory --backup-directory t    setq backup-directory-alist           --backup-directory     setq make-backup-files t                 backup of a file the first time it is saved        backup-by-copying t                 don t clobber symlinks       version-control t                   version numbers for backup files       delete-old-versions t               delete excess backup files silently       delete-by-moving-to-trash t       kept-old-versions 6                 oldest versions to keep when a new numbered backup is made  default  2        kept-new-versions 9                 newest versions to keep when a new numbered backup is made  default  2        auto-save-default t                 auto-save every buffer that visits a file       auto-save-timeout 20                number of seconds idle time before auto-save  default  30        auto-save-interval 200              number of keystrokes between auto-saves  default  300            Sensitive data  Another problem is that you don t want to have Emacs spread copies of files with sensitive data  Use this mode on a per-file basis   As this is a minor mode  for my purposes I renamed it sensitive-minor-mode   To enable it for all  vcf and  gpg files  in your  emacs use something like    setq auto-mode-alist        append         list                  vcf   gpg        sensitive-minor-mode                   auto-mode-alist     Alternatively  to protect only some files  like some  txt files  use a line like     - -mode asciidoc  mode sensitive-minor  fill-column 132- -   in the file

User · Answer

You can disable them altogether by   setq make-backup-files nil

[emacs] How do I control how Emacs makes backup files?

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