; Improve documentation of backing up files

* doc/emacs/files.texi (Backup Copying): Mention that
'backup-by-copying' is safer.  Document 'file-precious-flag'.
(Bug#71074)

(cherry picked from commit 5ab144c77cda1d56f0dd62606c316c712a0d2563)

diff --git a/doc/emacs/files.texi b/doc/emacs/files.texi
index af8d20782f85ecb494808cc964bcfb3ce63aedbe..1a4307aaabeaf091851d4c258e762ef8eb499e32 100644 (file)
--- a/doc/emacs/files.texi
+++ b/doc/emacs/files.texi
@@ -784,6 +784,14 @@ those previous versions.  If you want to be able to do that with files
 hosted by those services when editing them with Emacs, customize
 @code{backup-by-copying} to a non-@code{nil} value.
 
+@vindex file-precious-flag
+  Copying the old file for backup is also useful when editing precious
+files, because it makes sure the old file keeps its name if something
+fails between the backup and the saving of your edits.  Alternatively,
+you can customize @code{file-precious-flag} to a non-@code{nil} value,
+which implies backups by copying and also protects against I/O errors
+while saving your edits.
+
 @node Customize Save
 @subsection Customizing Saving of Files