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

my $line;
while (defined($line = <DATA>) )
{
    chomp $line;                        # line 7
    if ($line =~ s/\\$//)               # line 8
    {
        $line .= <DATA>;
        redo unless eof(DATA);
    }
    print "LINE: '$line'\n";
}

__DATA__
1 1
2 2
3 3
4 4 \
 4 4 \
  4 4
5 5