Hello babysFirstPerl, and welcome to the Monastery!

Am I correct in thinking that the file begins with a single header of $ARGV[0] lines and ends with a single footer of $ARGV[1] lines? If so, the following approach should do what you want. It reads the file exactly once, and processes it on-the-fly so that the number of lines held in memory never exceeds one plus the number of lines in the footer:

#! 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

[download]

Output:

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

 0:55 >

[download]

Update: A couple of additional points:

Hope that helps,

Athanasius <°(((>< contra mundum Iustus alius egestas vitae, eros Piratica,

In reply to Re: More efficient way to exclude footers by Athanasius
in thread More efficient way to exclude footers by babysFirstPerl

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