Re: why read only buffer?

[PJ Weisberg]

On Fri, Jul 6, 2012 at 12:44 PM, Alp Aker <alptekin.aker@gmail.com> wrote:
> On Fri, Jul 6, 2012 at 3:04 PM, notbob <notbob@nothome.com> wrote:
>> As you can see, it's a backup file.  So?  I can edit the regular file,
>> but not the backup (~) file.  Identical permissions.  WTF!?
>
> Use the command 'toggle-read-only' (default binding C-x C-q) if you
> want to edit a backup file.

That's deliberately there to stop you from accidentally modifying a
backup file when you meant to be working with the regular file.  If
you searched through the source you'd find this in files.el:

-----
  ;; Make people do a little extra work (C-x C-q)
  ;; before altering a backup file.
  (when (backup-file-name-p buffer-file-name)
    (setq buffer-read-only t))
-----

-PJ

Gehm's Corollary to Clark's Law: Any technology distinguishable from
magic is insufficiently advanced.