$numHeaders= $ARGV[0];
$numFooters= $ARGV[1];

# Read the file into memory
open (INPUT, $l_infile);
my @file = <INPUT>;
close INPUT;

# Treating the array as a scalar value gives you the number of lines
# (not that you really need to worry about this right now)
my $numLines = @file;

# Split the headers and footers into their own arrays
my @headers = splice @file, 0, $numHeaders;
my @footers = splice @file, $#file-$numFooters, $numFooters;

for my $line (@headers) {
   # do whatever you want with the headers
}

for my $line (@file) {
   # process your data
}

##</code><code>##

# Discard the headers and footers
splice @file, 0, $numHeaders;
splice @file, $#file-$numFooters, $numFooters;