#!perl -w
use strict;

my $file = 'c:/windows/bootstat.dat';
-e $file or die "no $file";

my $boot_days_ago = -M $file;
my $boot_secs_ago = 86400 * $boot_days_ago;
my $boot_time = int ( time - $boot_secs_ago) ;

while(1) {
    my $t =  time-$boot_time;
    printf  "%4d h  %2d m\r", int($t/3600), int(($t%3600)/60);
    sleep 1;
}