[geeks] Quick sed question

[Greg A. Woods]

[ On Saturday, June 22, 2002 at 11:49:23 (-0400), alex j avriette wrote: ]
> Subject: Re: [geeks] Quick sed question
>
> >> 	sed -e 's/^[ 	]*//'
> >
> > Or more efficiently :
> >
> > sed -e 's/^[     ]+//'
> 
> well sure its a little more efficient, but its not the same expression.

Well the requirements Josh stated would have been equally well met with
this expression:

 	sed -e 's/^[ 	][ 	]*//'

so the '+' form is equally correct for his needs.

(and if you think about the actual substitution that's happening its
obvious they both reduce to the very same result -- it's just that a
naive implementation of 'sed' can't give the necessary hints to the
regex compiler to make the match work exactly the same in both cases,
and thus the '+' form ends up being a lot faster to run)

-- 
								Greg A. Woods

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