Re: [PATCH 3/3] perf, tool: Add new event group management

[Peter Zijlstra]

On Wed, 2012-03-21 at 10:52 +0100, Ingo Molnar wrote:
> * Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:
> 
> > # echo {}
> > {}
> > # echo {en,dis}able
> > enable disable
> > 
> > 
> > It somehow special cases {}, which is horrible.
> 
> Oh, indeed: brace expansion and sequence expressions both use 
> curly braces:
> 
>  $ echo foo-{a,b,c}-bar
>  foo-a-bar foo-b-bar foo-c-bar
> 
>  $ echo {1..10}
>  1 2 3 4 5 6 7 8 9 10
> 
> Too bad, it would be rather intuitive. All the brace characters 
> are taken by Bash.
> 
> Maybe something like:
> 
>  $ echo /minor-faults,major-faults/
>  /minor-faults,major-faults/
> 
> although it looks a bit weird.
> 
> So ... how about using another grouping operator, such as '+'?
> 
> Something like:
> 
>  -e minor-faults+major-faults
> 
> While when comma separated they are not grouped, or so.

I would much prefer a syntax that's more natural but requires quoting
than one that's quirky and tailor made to avoid whatever current bash
does. For one, there's other shells out there that might have different
quoting needs and bash is of course free to extend its syntax.


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