An alternative to File::ReadBackwards would be the tac(1) command:

NAME
       tac - concatenate and print files in reverse

For example:

open(ELIF,"tac file.foo |")
  or die "Couldn't tac file: $!\n";
while (<ELIF>)
{
  push @lines,$_ if /criteria/;
  last if @lines > $n;
}
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