posix = require("posix")

sleep_duration = 1

stat = io.open('/proc/stat', 'r')
stat:setvbuf('no')

stat:seek('set', 5)
previousStats = stat:read()

posix.sleep(sleep_duration)

stat:seek('set', 5)
currentStats = stat:read()


user, nice, system, idle, iowait, irq, softirq, steal, guest, guest_nice = string.match(currentStats, '(.*) +(.*) +(.*) +(.*) +(.*) +(.*) +(.*) +(.*) +(.*) +(.*)')

prevuser, prevnice, prevsystem, previdle, previowait, previrq, prevsoftirq, prevsteal, prevguest, prevguest_nice = string.match(previousStats, '(.*) +(.*) +(.*) +(.*) +(.*) +(.*) +(.*) +(.*) +(.*) +(.*)')

    user = tonumber(user)
    nice = tonumber(nice)
    system = tonumber(system)
    idle = tonumber(idle)
    iowait = tonumber(iowait)
    irq = tonumber(irq)
    softirq = tonumber(softirq)
    steal = tonumber(steal)
    guest = tonumber(guest)
    guest_nice = tonumber(guest_nice)

    prevuser = tonumber(prevuser)
    prevnice = tonumber(prevnice)
    prevsystem = tonumber(prevsystem)
    previdle = tonumber(previdle)
    previowait = tonumber(previowait)
    previrq = tonumber(previrq)
    prevsoftirq = tonumber(prevsoftirq)
    prevsteal = tonumber(prevsteal)
    prevguest = tonumber(prevguest)
    prevguest_nice = tonumber(prevguest_nice)


PrevIdle = previdle + previowait
Idle = idle + iowait

PrevNonIdle = (prevuser + prevnice + prevsystem + previrq + prevsoftirq + prevsteal)
NonIdle = (user + nice + system + irq + softirq + steal)

PrevTotal = (PrevIdle + PrevNonIdle)
Total = (Idle + NonIdle)

totald = (Total - PrevTotal)
idled = (Idle - PrevIdle)

CPU_Percentage = (totald - idled) / totald * 100



print(CPU_Percentage)