#!/usr/bin/env perl
use strict;
use warnings;

$| = 1;
my $i=0;

while ( $i < 10 ) {
    print "$i\r";
    $i++;
    sleep 1;
}

while ( $i >= 0 ) {
    print " " x 80 . "\r";
    print "$i\r";
    $i--;
    sleep 1;
}

print "\n";