bash expansion help

[Lennart Sorensen]

On Mon, Feb 05, 2007 at 12:57:41PM -0500, Steve Harvey wrote:
>   bash will happily do recursive brace expansion on it's input:
> 
> $ #I'm using a pared down version for brevity
> $ echo GENERIC_ARM ARM{610,710,_{SA110,SA1100,XSCALE}}
> GENERIC_ARM ARM610 ARM710 ARM_SA110 ARM_SA1100 ARM_XSCALE
> $ # Presuming it's a variable within a script that we want to expand
> $ arm_opts="GENERIC_ARM ARM{610,710,_{SA110,SA1100,XSCALE}}"
> $ echo $arm_opts
> GENERIC_ARM ARM{610,710,_{SA110,SA1100,XSCALE}}
> $ # not what we want, therefore pipe it into bash
> 
> Can you find a way do do this with less overhead?  I count two
> invocations of the shell, one implicit by using `` and one explicit.

Hmm, I missed that if was expanding $arm_opts.  I had been playing with
it as just foo=`echo ARM{610,710,_{SA110,SA1100,XSCALE}}` which didn't
need another shell.  Given the extra variable, no I don't think I can
find a shorter method.  Not sure eval or anything else would do it, but
it would take more characters to do it for sure.

--
Len Sorensen
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