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Subject: Re: need bash indirect variable help
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From: floyd@apaflo.com (Floyd L. Davidson)
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Date: Sun, 08 Jun 2014 14:50:50 -0800
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Xref: csiph.com comp.os.linux.misc:11227

Todd <Todd@invalid.invalid> wrote:
>On 06/08/2014 01:31 PM, Jerry Peters wrote:
>>
>> In bash:
>> ~$ x=z
>> ~$ a=x
>> ~$ echo ${!a}
>> z
>>
>
>Hi Jerry,
>
>Thank you!
>
>What exactly does the "!" do?

See the bash man page, under the heading of "Parameter
Expansion", where the third paragraph down describes it.
Indirection, or they suggest "indirect expansion", uses
the contents of a variable as a the variable acted on.

It is the equivalent of the also suggested eval command,
which might be prefered just because it will be more
obvious what the eval command is doing while the bang
operator will be easily missed or confused.

-- 
Floyd L. Davidson                         http://www.apaflo.com/
Ukpeagvik (Barrow, Alaska)                      floyd@apaflo.com