Re: command for swapping of two files or two dirs?

[Alex fxmbsw7 Ratchev]

maybe mmv interparses quotes, like xargs
try ${var@Q} as args

On Fri, Mar 26, 2021 at 10:36 PM Reuti <reuti@staff.uni-marburg.de> wrote:
>
>
> > Am 26.03.2021 um 22:21 schrieb Peng Yu <pengyu.ut@gmail.com>:
> >
> > The problem is that the swap based on multiple commands is not atomic.
> > With multiple commands, wouldn't it cause complications for error
> > recovery? Also, is it safe? If there is any malicious program delete
> > some files during the process?
>
> `mmv` can handle multiple renames (without overwriting each others file), but 
> with multiple file pairs it won't handle filenames which space characters or 
> alike in a proper way (as it reads the filename pairs directly from stdin).
>
> $ function swap() { mmv <<<"$1 $2"$'\n'"$2 $1"; }
>
> It would be a good addition to `mmv` to handle an atomic swap operation too.
>
> -- Reuti
>
>
> >
> > On 3/26/21, Alex fxmbsw7 Ratchev <fxmbsw7@gmail.com> wrote:
> >> i agree to all excepts the srandom thingy
> >> a [[ -e loop passthru maybe.. like always
> >>
> >> On Fri, Mar 26, 2021 at 9:58 PM Greg Wooledge <greg@wooledge.org> wrote:
> >>>
> >>> On Fri, Mar 26, 2021 at 09:18:10PM +0100, Alex fxmbsw7 Ratchev wrote:
> >>>> swap() { declare t= tt= ; [[ $# != 2 ]] && return 1
> >>>> mv "$1" "${t:=/tmp/$SRANDOM}"
> >>>> mv "$2" "${tt:=/tmp/$SRANDOM}"
> >>>> mv "$t" "$2"
> >>>> mv "$tt" "$1"
> >>>> }
> >>>
> >>> 1) Use mktemp(1) or tempfile(1) or whatever.  Your $SRANDOM hack has
> >>>   security problems.
> >>>
> >>> 2) Don't move the file to /tmp.  That might be on a different file
> >>> system.
> >>>   You want to keep the file within its current directory, as that's the
> >>>   only place you can be sure isn't on another file system.
> >>>
> >>> 3) There should only need to be three moves.
> >>>
> >>> 4) You probably want && between the moves, to abort if something goes
> >>>   wrong.
> >>>
> >>
> >>
> >
> >
> > --
> > Regards,
> > Peng
> >
>
> --
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