On Wed, Apr 06, 2016 at 04:26:52PM -0500, Derek Martin wrote:
> Hi Cameron,
>
> On Wed, Apr 06, 2016 at 09:50:28AM +1000, Cameron Simpson wrote:
> > Consider using ${1+"$@"}, which preserves quoting.
>
> How is this better than just "$@"? I believe it's non-portable (and
> for that reason I'm less familiar with that syntax) but if I
> understand correctly it expands like:
>
> if $1 is set use that, otherwise use "$@" (all arguments, individually
> quoted)
>
> It seems as though this always evaluates to $1 (since if $1 is unset,
> $@ is also necessarily empty)... which I think is not what is needed
> here. Am I mistaken? I believe just "$@" (including the quotes) is
> what you want here.
In the distant past constructions like that were needed because of a
bug in the shells. If you had no arguments, "$@" was passed as "",
a single null argument. Now it is correctly passed as no arguments.
OT BTW I typically used ${@+"$@"} and playing with it after seeing
this thread discovered a bug in handling it in ksh but not bash or zsh.
Ksh only checks $1 for set/null rather than the entire list of args.
jl
--
Jon H. LaBadie j...@jgcomp.com
11226 South Shore Rd. (703) 787-0688 (H)
Reston, VA 20190 (703) 935-6720 (C)
