#! perl -slw
use strict;

open IN, '<', $ARGV[ 0 ] or die $!;

$/ = 'head';
 while( <IN> ) {
 	local $/ = 'tail';
 	print scalar <IN>;
 }
close IN;
__END__
P:\test>type junk.txt
The quick brown fox jumps over the lazy dog           0001
head The quick brown fox jumps over the lazy dog      0002
The quick brown fox jumps over the lazy dog           0003
The quick brown fox jumps over the lazy dog           0004
The quick brown fox jumps over the lazy dog           0005
tail The quick brown fox jumps over the lazy dog      0006
The quick brown fox jumps over the lazy dog           0007
The quick brown fox jumps over the lazy dog           0008
headThe quick brown fox jumps over the lazy dog       0009
The quick brown fox jumps over the lazy dog           0010
tail The quick brown fox jumps over the lazy dog      0011
The quick brown fox jumps over the lazy dog           0012

P:\test>235232 junk.txt
 The quick brown fox jumps over the lazy dog      0002
The quick brown fox jumps over the lazy dog           0003
The quick brown fox jumps over the lazy dog           0004
The quick brown fox jumps over the lazy dog           0005
tail
The quick brown fox jumps over the lazy dog           0009
The quick brown fox jumps over the lazy dog           0010
tail