bug#4403: 23.1; find-dired: use "find -exec ls -ld {} +" or "find -ls" where available

bug#4403: 23.1; find-dired: use "find -exec ls -ld {} +" or "find -ls" where available

[trentbuck]

Recent versions of GNU find support the expressions

    find <query> -exec ls -ld {} +

and

    find <query> -ls

I believe these are also part of recent versions of the POSIX spec.

It would be great if M-x find dired RET automatically used these forms
instead of the less efficient

    find <query> -exec ls -ld {} \;

that it currently uses.  It would also mean that the output would line
up better, since

    ls foo bar baz

will try to align the three lines, whereas

    ls foo ; ls bar ; ls baz

won't.

bug#4403: 23.1; find-dired: use "find -exec ls -ld {} +" or "find -ls" where available

[Glenn Morris]

trentbuck@gmail.com wrote:

> Recent versions of GNU find support the expressions
>
>     find <query> -exec ls -ld {} +
>
> and
>
>     find <query> -ls
>
> I believe these are also part of recent versions of the POSIX spec.
>
> It would be great if M-x find dired RET automatically used these forms

You can use something like:

(setq find-ls-option
      (let ((help (shell-command-to-string (format "%s --help" find-program))))
        (if (string-match " -ls\\>" help)
            '("-ls" . "-lids")
          (if (string-match "{} \\+" help)
              '("-exec ls -ld {} +" . "-ld")
            '("-exec ls -ld {} \\;" . "-ld")))))

The -ls version changes the output format.

> It would also mean that the output would line up better

Surely dired already takes care of the alignment?

bug#4403: 23.1; find-dired: use "find -exec ls -ld {} +" or "find -ls" where available

[Trent W. Buck]

On Mon, Sep 14, 2009 at 10:50:04PM -0400, Glenn Morris wrote:
>> It would be great if M-x find dired RET automatically
>
> You can use something like:
>
> (setq find-ls-option
>       (let ((help (shell-command-to-string (format "%s --help" find-program))))
>         (if (string-match " -ls\\>" help)
>             '("-ls" . "-lids")
>           (if (string-match "{} \\+" help)
>               '("-exec ls -ld {} +" . "-ld")
>             '("-exec ls -ld {} \\;" . "-ld")))))

True.  I guess I should have mentioned: I tried that a couple of years
ago, but it broke down when I tried TRAMP to a host that doesn't
support -exec {} + -- namely some FC3 and CentOS 4 servers.  I suppose
that's really a separate TRAMP wishlist bug.

(The same thing happens with setting dired-listing-switches to "-Alh",
but I very rarely connect to a non-GNU server.)

> The -ls version changes the output format.
>
>> It would also mean that the output would line up better
>
> Surely dired already takes care of the alignment?

Nope.  AFAIK M-x dired is aligned only because ls(1) handles
alignment.  find-dired isn't aligned because ls(1) is called on files
one at a time.  In some environments, GNU ls called on a single file
would align to a tab stop, so find-dired still *mostly* aligned things
nicely.  Some (recent? locale-dependent?) versions didn't align to a
tab stop, so find-dired output was very hard to read, being completely
unaligned.

UPDATE: apparently I was wrong, because this is aligned normally, but
broken in find-dired:

    find . \( -type d \) -exec ls -ldh {} +

    (setq  find-ls-option '("-exec ls -ldh {} +" . "-ldh"))

e.g. dired:

    drwxr-xr-x   2 twb twb       12K 2009-07-06 13:53 SinFest
    drwxr-xr-x   2 twb twb        4.0K 2009-09-01 21:55 VGCats
    drwxr-xr-x   2 twb twb       12K 2009-09-15 11:39 xkcd

vs. find directly in shell:

    drwxr-xr-x  2 twb twb  12K 2009-07-06 13:53 ./SinFest
    drwxr-xr-x  2 twb twb 4.0K 2009-09-01 21:55 ./VGCats
    drwxr-xr-x  2 twb twb  12K 2009-09-15 11:39 ./xkcd

bug#4403: 23.1; find-dired: use "find -exec ls -ld {} +" or "find -ls" where available

[Glenn Morris]

Version: 24.1

find-dired now uses `find -ls' or `find -exec +' where available.