open RH, "2.txt" or die $!;
/^(.+?)\s*$/ and push @new_content, $1 while <RH>; 
close RH;
open RH, "1.txt" or die $!;
/^\d+\s*(.+?)\s*$/ and push @old_content, $1 while <RH>;
close RH; open WH, ">1.txt" or die $!;

for(@new_content){
	$count++;
	print WH "$_ $old_content[--$counter]\n"
}