usage-cpu

#!/bin/sh

CPUS=$(getconf _NPROCESSORS_ONLN)
ITER=$(seq 1 $(expr $CPUS + 1))

for j in $ITER; do
    FROM=($(sed "${j}q;d" /proc/stat))
    NAME[j]=$(echo ${FROM[0]} | tr a-z A-Z)
    FROM_TIME_IDLE[j]=${FROM[4]}
    FROM_TIME_TOTAL[j]=$((${FROM[1]}  + ${FROM[2]}  + ${FROM[3]}  + ${FROM[4]}))
done

sleep 0.25

for j in $ITER; do
    TO=($(sed "${j}q;d" /proc/stat))
    TO_TIME_IDLE=${TO[4]}
    TO_TIME_TOTAL[j]=$((${TO[1]}  + ${TO[2]}  + ${TO[3]}  + ${TO[4]}))

    # TODO: Fix divide-by-zero
    DELTA_TIME=$((FROM_TIME_TOTAL[j] - TO_TIME_TOTAL[j]))
    if [[ $DELTA_TIME > 0 ]]
    then
        PERCENT[j]=$((100 * (FROM_TIME_TOTAL[j] - TO_TIME_TOTAL[j] - ${FROM_TIME_IDLE[j]}  + $TO_TIME_IDLE)  / $DELTA_TIME))
    else
        PERCENT[j]=0
    fi
done

NAME[1]=" AVG"
for j in $ITER; do
    PERCENT_PADDED=$(echo ${PERCENT[$j]} | sed -e :a -e 's/^.\{1,2\}$/ &/;ta')
    echo -e "${PERCENT[$j]}\t ${NAME[$j]}: "$PERCENT_PADDED"% "
done

echo -ne "\0"