#!/usr/bin/perl
print "enter the START number: \n";
$number1 = <STDIN>;
print "enter END number: \n";
$number2 = <STDIN>;
@list=($number1..$number2);
print "@list\n";

# if the file already exists.
open OUTFILE, ">>/path/to/outfile" or die "Cannot open $!\n";
# if you want to create new file each time the program is executed.
# open OUTFILE, ">/path/to/outfile" or die "Cannot open $!\n";

map { print OUTFILE $_, "\n"; } @list;

close (OUTFILE);