You've copied the value pointed to by the reference. When you copy a reference, you're still pointing to the same value. When you copy a dereference, you get a fresh copy of the value. 

my $file_name = shift;
my $lines_in = shift;

# skip a few

    $$lines_in .= $_;

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In reply to Re: Sub Params as references by chromatic
in thread Sub Params as references by Maclir

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