#!/bin/bash
then=$(sysctl kern.boottime | awk '{print $5}' | sed "s/,//")
now=$(date +%s)
diff=$(($now-$then))

days=$(($diff/86400));
diff=$(($diff-($days*86400)))
hours=$(($diff/3600))
diff=$(($diff-($hours*3600)))
minutes=$(($diff/60))
seconds=$(($diff-($minutes*60)))

printf "Uptime: %dd%02dh%02dm%02ds" $days $hours $minutes $seconds