backup files on mounted filesystems

backup files on mounted filesystems

[Michael Bane]

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Hi
I've noticed that I do not seem to get automatic backup files if I am on a mounted filesystem (eg /tmp). Is there a setting for enabling this functionality?
Many thanks,


Michael Bane || Snr Research Applications & Collaboration Consultant || RAC Team || IT Services || The University of Manchester || 0161 306 6652 || michael.bane@manchester.ac.uk || @mkbane_mcr || http://www.rac.manchester.ac.uk || http://www.manchester.ac.uk/rac


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Re: backup files on mounted filesystems

[Eli Zaretskii]

> From: Michael Bane <michael.bane@manchester.ac.uk>
> Date: Fri, 12 Apr 2013 13:29:49 +0100
> 
> I've noticed that I do not seem to get automatic backup files if I am on a mounted filesystem (eg /tmp). Is there a setting for enabling this functionality?

Not mounted filesystems, but specifically /tmp, because it's a place
where you place temporary files.

To customize this, define your own function instead of
normal-backup-enable-predicate, and set backup-enable-predicate to
that function.

Re: backup files on mounted filesystems

[Michael Bane]

On 12 Apr 2013, at 15:57, Eli Zaretskii wrote:

>> From: Michael Bane <michael.bane@manchester.ac.uk>
>> Date: Fri, 12 Apr 2013 13:29:49 +0100
>> 
>> I've noticed that I do not seem to get automatic backup files if I am on a mounted filesystem (eg /tmp). Is there a setting for enabling this functionality?
> 
> Not mounted filesystems, but specifically /tmp, because it's a place
> where you place temporary files.

As well as /tmp (on whichever OS I have tried) I also see this issue on MacOS where work/ is a mounted (encrypted) filesystem

Thanks, Michael

> 
> To customize this, define your own function instead of
> normal-backup-enable-predicate, and set backup-enable-predicate to
> that function.
> 

Re: backup files on mounted filesystems

[Eli Zaretskii]

> From: Michael Bane <michael.bane@manchester.ac.uk>
> CC: "<help-gnu-emacs@gnu.org>" <help-gnu-emacs@gnu.org>
> Date: Fri, 12 Apr 2013 16:12:11 +0000
> 
> >> I've noticed that I do not seem to get automatic backup files if I am on a mounted filesystem (eg /tmp). Is there a setting for enabling this functionality?
> > 
> > Not mounted filesystems, but specifically /tmp, because it's a place
> > where you place temporary files.
> 
> As well as /tmp (on whichever OS I have tried) I also see this issue on MacOS where work/ is a mounted (encrypted) filesystem

If work/ is temporary-file-directory, then that's again Emacs in
action.  Otherwise, it's not Emacs's fault.

Re: backup files on mounted filesystems

[Michael Bane]

On 12 Apr 2013, at 18:52, Eli Zaretskii wrote:

>> From: Michael Bane <michael.bane@manchester.ac.uk>
>> Date: Fri, 12 Apr 2013 17:43:44 +0000
>> 
>> Hi again & thanks for replies
>> 
>> I've not set work as a temp file directory (explicitly) - how would I check?
>> When I look I do see that once upon a time backups must have worked since there's a example.txt~ in there
> 
> "M-x load-library RET files.el RET", then instrument
> normal-backup-enable-predicate with Edebug, edit file in work/, type
> "C-x C-s", and step through that function to see what's going on.

Hi Eli and emac-ers

Sorry but I've no idea what Edebug is nor the instrumentation steps? 
NB I'm using the "-nw" version of emacs on a Mac

Yours, Michael

Re: backup files on mounted filesystems

[Eli Zaretskii]

> From: Michael Bane <michael.bane@manchester.ac.uk>
> Date: Tue, 16 Apr 2013 15:34:22 +0100
> Cc: help-gnu-emacs@gnu.org
> 
> > "M-x load-library RET files.el RET", then instrument
> > normal-backup-enable-predicate with Edebug, edit file in work/, type
> > "C-x C-s", and step through that function to see what's going on.
> 
> Hi Eli and emac-ers
> 
> Sorry but I've no idea what Edebug is nor the instrumentation steps? 
> NB I'm using the "-nw" version of emacs on a Mac

Edebug works in the -nw session as well.

Edebug is described in the ELisp manual.

After "M-x load-library" as above, visit the file file.el, search for
the normal-backup-enable-predicate function, and with cursor somewhere
inside that function, type "M-x edebug-defun RET".  Then edit the file
in your work/ directory and save it.  When you save it, the debugger
will kick in, and you can step through normal-backup-enable-predicate
by pressing SPC.  Watch the control flow and the results of evaluating
each Lisp form that are displayed in the echo area.

Re: backup files on mounted filesystems

[Stefan Monnier]

> I've noticed that I do not seem to get automatic backup files if I am
> on a mounted filesystem (eg /tmp).

On Unix, you can't basically access a file unless it's on
a mounted filesystem.  Even "/" is a "mounted filesystem".

But yes, /tmp is treated specially in Emacs.  You can set
backup-enable-predicate to another function if you want to change
this behavior.


        Stefan