#!/bin/bash

# get the lifetime cpu utilization percent of pid (the one argument)

pidfile="/proc/$1/stat"
ticks=$(getconf CLK_TCK)
uptime=$(awk '{print $1}' "/proc/uptime")
utime=$(awk '{print $14}' "$pidfile")
stime=$(awk '{print $15}' "$pidfile")
cutime=$(awk '{print $16}' "$pidfile")
cstime=$(awk '{print $17}' "$pidfile")
starttime=$(awk '{print $22}' "$pidfile")

echo "($utime + $stime + $cutime + $cstime) / ($uptime * $ticks - $starttime)" | bc -l