Backup
Backup Deletion
If you choose to have a single backup file (this is the default),
the backup file's name is constructed by appending `~' to the
file name being edited; thus, the backup file for `eval.c' would
be `eval.c~'.
If you choose to have a series of numbered backup files, backup file
names are made by appending `.~', the number, and another `~' to
the original file name. Thus, the backup files of `eval.c' would be
called `eval.c.~1~', `eval.c.~2~', and so on, through names
like `eval.c.~259~' and beyond.
If protection stops you from writing backup files under the usual names,
the backup file is written as `%backup%~' in your home directory.
Only one such file can exist, so only the most recently made such backup is
available.
The choice of single backup or numbered backups is controlled by the
variable version-control. Its possible values are
t
|
Make numbered backups. |
nil
|
Make numbered backups for files that have numbered backups already. Otherwise, make single backups. |
never
|
Do not in any case make numbered backups; always make single backups. |
You can set version-control locally in an individual buffer to
control the making of backups for that buffer's file. For example,
Rmail mode locally sets version-control to never to make sure
that there is only one backup for an Rmail file. See Locals.
If you set the environment variable VERSION_CONTROL, to tell
various GNU utilities what to do with backup files, Emacs also obeys the
environment variable by setting the Lisp variable version-control
accordingly at startup. If the environment variable's value is `t'
or `numbered', then version-control becomes t; if the
value is `nil' or `existing', then version-control
becomes nil; if it is `never' or `simple', then
version-control becomes never.
Backup
Backup Deletion