#!/usr/bin/perl -w
use strict;
use File::ReadBackwards;
my @lines = ();
my $n = 10;
my $elif = File::ReadBackwards->new('somefile') || die $!;
while(defined(my $line = $elif->readline())){
    unshift @lines, $line if $line =~ /criteria/;
    last if @lines >= $n
}
print @lines;
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