On 05/03/2024 04:10, Paul Eggert wrote:
On 3/4/24 16:43, Dominique Martinet wrote:
Adding Rob to the loop because this impacts compatibility with
toybox/maybe busybox implementations
Busybox does not use RENAME_EXCHANGE, so this isn't a Busybox issue.
Toybox mv added -x to its development version yesterday:
https://github.com/landley/toybox/commit/a2419ad52d489bf1a84a9f3aa73afb351642c765
so there's little prior art there, and there's still plenty of time to
fix its problems before exposing it to the world.
I also see --swap mostly used by scripts and this actually feels a bit
dangerous to me -- I'd *always* use this with -T.
Yes, it's a problem.
By "see --swap mostly used by scripts" I assume you mean scripts that
haven't been written yet, assuming that nobody had -x until yesterday....
(by the way, what's this "rename" command you speak of?
https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/
Now that I've looked into it further, util-linux already has an "exch"
command that does exactly what you want. This is the command that toybox
should implement rather than try to simulate it with "mv -x" (which
causes all sorts of problems).
That is, toybox should revert yesterday's change to "mv", and should
implement "exch" instead.
I think having the functionality in mv(1) is better than in rename(1),
but since exch(1) is already released that's probably
the best place for this functionality now.
A separate exch command may be overkill for just this,
but perhaps related functionality might be added to that command in future.
For e.g. some of the discussed functionality for a "replace" command
might reside there.
So I think I'll remove the as yet unreleased mv --swap from coreutils, given
that
util-linux is as widely available as coreutils on GNU/Linux platforms.
cheers,
Pádraig
