Another quick question: What is your purpose for this code:

my @crl = grep { /^$c*/ } @lfq;
my @res = grep { !/^$c*/ } @lfq;
push @crl, @res;
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1. You carefully filter all the records from @lfq that start with $c into @crl;
2. Then you equally carefully extract all the records from @lfq that don't start with $c into @res;
3. Then you put all those carefully selected records back together in the same array.

Effectively the result of those 3 expensive lines is the same as: @crl = @lfq; apart from the side effect of retaining some records in @res that could have been obtains much more efficiently by omitting 2 of the 3 lines!?

It might be better if instead of showing how you are doing things; you told use what you are trying to do in terms of inputs -- files and console -- and expected output.

At the moment it is hard to know where to start to help you as the code you've posted doesn't make a whole lot of sense and there doesn't appear to be a question.