Re: backup method

[Han Boetes <han@mijncomputer.nl>]

Richard Stallman wrote:
> Han Boetes wrote:
> > The default backup method is mv and then create a new file.
> > That's nice if you really want to keep the timestamp intact.
> > But if you use emacs with crontab -e you remove the tmpfile
> > and since the filedescriptor is still open your update to your
> > cron is lost -- without warning. It was pretty hard to
> > discover why this happened.
> >
> > So I would like to suggest to make backup by copying the
> > default.
>
> I won't change it in general, but we could probably arrange to
> use backup by copying for *this specific case*. Can you give a
> precise recipe for distinguishing this case--a regexp for these
> file names, perhaps?

My initial suggestion to do backup by copying is not the right
solution for the problem at all. I explained the right solution in
another message in this thread.

My prove is:

  unset TMP TMPDIR
  export VISUAL='emacs -q' # which does backup by moving by default
  crontab -e

And you can edit your crontab fine since emacs won't make a backup
of files in /tmp

  export TMP=~/.tmp; export TMPDIR=~/.tmp
  export VISUAL='emacs -q' # which does backup by moving by default
  crontab -e

And you can no longer edit crontabs since emacs will make a backup
of files in /tmp.

This problem is caused by the fact that not all programs honour
TMPDIR and still make tmpfiles in /tmp. Or that emacs does not
anticipate this.

I described the solution in another message in this thread.




# Han