#! perl
use strict;
use warnings;

my $header_lines = $ARGV[0] // 0;
my $footer_lines = $ARGV[1] // 0;

<DATA> for 1 .. $header_lines;   # Throw away the header

my @lines;

while (<DATA>)
{
    push @lines, parse_line($_);
    print shift @lines if @lines > $footer_lines;
}

sub parse_line
{
    my ($line) = @_;
    # ...Parse $line...
    return $line;
}

__DATA__
Header 1
Header 2
Text 1
Text 2
Text 3
Text 4
Text 5
Footer 1
Footer 2
Footer 3

##</code><code>##

 0:50 >perl 1348_SoPW.pl 2 3
Text 1
Text 2
Text 3
Text 4
Text 5

 0:55 >