[ILUG] sed question

[John Allen]

On Friday 20 February 2004 09:13, Niall O Broin wrote:
> On Friday 20 February 2004, john.allen at dublinux.net (John Allen) wrote:
> >> Two characters less to type, and just a tiny bit less satisfying is:
> >>
> >>
> >> perl -ne 'if (/1^(2)/) {print} else { exit if $1}' humungous_file
> >
> >This one does not work though.
>
> That's right - I've no idea where the 1 after the / came from :-)
>
> However, the  whole thing is moot as Padraig is in a quest for speed, so
> the capture here is a bad idea (because it's relatively slow). Anyway, C
> and readline is probably the way he'll go. My Perl solution was written

Well I suppose it depends how far down the file the 2's are. If they are 
relatively near the top, it wouldn't make much difference. That said it would 
probably be just as fast in Perl with simpler pattern matching.

So with a quick rehash of Country Kev's script, I'd be surprised if C were any 
quicker.

perl -e 'while (<>) {
            last if ($_ eq "2")
        }
        print;
        while (<>) {
            exit if (!$_  eq "2");
            print
        }' file

> for conciseness and cuteness, not speed. And unlike a lot of Perl
> one-liners, it was understandable by mortals.
>
>
> Niall

-- 
John Allen,                          mailto:john.allen at dublinux.net
MandrakeClub Silver Member.          http://www.dublinux.net

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