#!/usr/bin/perl -w
use strict;

my $in_file  = 'file1.txt';
my $out_file = 'file2.txt';

open IN,  "< $in_file"  or die "Can't open $in_file for reading: $!";
open OUT, "> $out_file" or die "Can't open $out_file for writing: $!";

binmode IN; # in case we're on a Windows system
binmode OUT;

my $buffer;
my $flag = 0;
my $last_byte = 0;

while ( read( IN, $buffer, 1024 ) ) {
	if ( $last_byte and substr( $buffer, 0, 1 ) == 0x0A ) {
		$flag = 1;
		$buffer = substr( $buffer, 1 );
	} else {
		$last_byte = 0;
	}
    if ( $buffer =~ /\x0D\x0A/ ) {
		$flag = 1;
		$buffer =~ s/(?:[^\x0D]|\x0D(?!\x0A))*//;
	}
	$last_byte = 1 if substr( $buffer, -1 ) == 0x0D;
	
	last if $flag;
}

if ( $flag ) {
	print OUT $buffer or die "Could not write data to $out_file: $!";
	
	while ( read( IN, $buffer, 1024 ) ) {
		print OUT $buffer or die "Could not write data to $out_file: $!";
	}
} else {
	warn "Did not find '0x0D 0x0A' in $in_file";
}