Re: [Help-bash] bash4-3 ,in configure file. help!

[Greg Wooledge]

On Tue, Nov 08, 2016 at 10:00:30PM +0800, Ta wrote:
> for bash4-3 ,in configure file:
> if test -n "${ZSH_VERSION+set}" && (emulate sh) >/dev/null 2>&1; then :
>   emulate sh
>   NULLCMD=:
>   # Pre-4.2 versions of Zsh do word splitting on ${1+"$@"}, which
>   # is contrary to our usage.  Disable this feature.
>   alias -g '${1+"$@"}'='"$@"'
>   setopt NO_GLOB_SUBST
> 
> 
> 
> 
>  what ${ZSH_VERSION+set} will do?

It is testing whether the variable ZSH_VERSION is set.
See http://mywiki.wooledge.org/BashFAQ/083

... which I see has been hacked apart by the optimizers, who don't
understand that the page is intended to be *read by humans*, not
to be a platform for showing how cleverly they can code.  An older
version is simpler and has more explanation:

http://mywiki.wooledge.org/BashFAQ/083?action=recall&rev=11

> what command  the emulate is ?why i  cannot find the shell?

I'm guessing it's a zsh command.  As you can see, it's only run when
we have detected that we're being executed by zsh (as indicated by
the test for the ZSH_VERSION variable being set).

> what setopt NO_GLOB_SUBST means?

It could be another zsh command.  All I know is that it's not a bash
command.