linux下模拟CPU占用100%小程序

#! /bin/sh 
# filename killcpu.sh
if [ $# -ne 1 ] ; then
  echo "USAGE: $0 <CPUs>|stop"
  exit 1;
fi

stop()
{
 while read LINE
  do
    kill -9 $LINE
    echo "kill $LINE sucessfull"
  done < pid.txt
 cat /dev/null > pid.txt
}

start()
{
  echo "u want to cpus is: "$1
  for i in `seq $1`
do
  echo -ne " 
i=0; 
while true
do
i=i+1; 
done" | /bin/sh &
  pid_array[$i]=$! ;
done

for i in "${pid_array[@]}"; do
  echo ‘pid is: ‘ $i ‘;‘;
  echo $i >> pid.txt
done
}

case $1 in
   stop)
    stop
  ;;
   *)
   start $1
;;
esac