#!/usr/bin/perl -w
use strict;
use Time::Piece;
use Time::Duration;
use IO::File;

my ( $uptime ) = (
    IO::File->new('/proc/uptime') or die "No! Can't open!: $!\n"
)->getline =~ /^ (\d[\d.]+) \s+ (\d[\d.]+)$/x or die "Invalid uptime!\n";

my $now = Time::Piece->new;
my $boot = $now-$uptime;

printf <<"EOF", duration($uptime), $boot->cdate, $now->cdate;
Uptime: %s
Boot:   %s
Now:    %s
EOF