This is well known, but DON'T use $&, as it will grind your program to a complete halt.

Next, do the sorting while you're processing the input:

open(my $IN,'<','in.txt') || die "cannot open in.txt - $!\n";
my @output;
while(<$IN>)
{
        next if m/^\n/;
        push (@output, $_);
        @output = sort @output;
}

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Software speaks in tongues of man.
Stop saying 'script'. Stop saying 'line-noise'.
We have nothing to lose but our metaphores.

In reply to Re: Sort lines in a file by Erez
in thread Sort lines in a file by blackdragoen

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