bug#11815: 24.1; Confusing behavior of & in Dired

[John Wiegley]

If I mark several files in dired and press !, I can execute:

    rsync -av * jw:/srv/ftp/pub

I can also run:

    rsync -av * jw:/srv/ftp/pub &

But if I type &, I cannot run:

    rsync -av * jw:/srv/ftp/pub

Because this is equivalent to:

    rsync -av * jw:/srv/ftp/pub * &

It actually decribes this behavior in the docstring: with the & command, if no
& appears at the end of the line (which makes little sense, since I pressed &
to indicate it was asynchronous), Dired adds "* &".  ??

I think that the following equivalence should hold:

    ! COMMAND & == & COMMAND

The fix is simply to change the two lines in `dired-do-async-shell-command'
which append " *" to the end of the line to read:

  (unless (string-match "[ \t][*?][ \t]" command)
    (setq command (concat command " *")))

Thanks,
  John

In GNU Emacs 24.1.1 (x86_64-apple-darwin11.4.0, Carbon Version 1.6.0 AppKit 
1138.47)
 of 2012-06-28 on vulcan.local