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Re: T/F var expansion?

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  Re: T/F var expansion? Stephane Chazelas <stephane.chazelas@gmail.com> - 2019-07-29 10:28 +0100

#15257 — Re: T/F var expansion?

2019-07-28 21:17:43 -0700, L A Walsh:
> Is there a T/F var expansion that does:
>  
>     var=${tst:+$yes}${tst:-$no}
> 
> but with yes/no in 1 expansion?
[...]

You can also do:

no_yes=(no yes)
echo "${no_yes[${var+1}]}"

For the reverse:

echo "${no_yes[!0${var+1}]}"

See also:

map=(unset empty non-empty)
echo "${map[${var+1}+0${var:+1}]}"

-- 
Stephane

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