Monitor CPU per Core

CPUs-monitor.sh

#!/bin/bash

function getCPU(){
  LCPU=`grep "^processor" /proc/cpuinfo | sort -u  | wc -l`
  echo -n $LCPU-1
}

function getCpuUtilizationByCore(){
  # Format: cpu<Number>
  local CoreName="$1"
  
  #cpu_util=<(grep $CoreName /proc/stat) <(sleep 1 && grep $CoreName /proc/stat) | awk -v RS="" '{print ($13-$2+$15-$4)*100/($13-$2+$15-$4+$16-$5)}'  #PERMISSION DENIED
  cpu_util=$(awk '{u=$2+$4; t=$2+$4+$5; if (NR==1){u1=u; t1=t;} else print ($2+$4-u1) * 100 / (t-t1); }' <(grep $CoreName /proc/stat) <(sleep 1;grep $CoreName /proc/stat) | cut -d "." -f 1)
  echo -n "${cpu_util}"
}

CPUcount=$(getCPU);
for (( i=0; i<=$CPUcount; i++ )) do
   CoreUsage=$(getCpuUtilizationByCore "cpu$i")  
   echo "CPU Core $i : $CoreUsage"; 
done

#keyword: cpu, core, monitor, flamegraph, debug

# OUTPUT
# test with "stress --cpu 2"
CPU Core 0 : 100
CPU Core 1 : 42
CPU Core 2 : 2
CPU Core 3 : 100