Bash Shell Script: Print CPU Usage for a Given Program to a Terminal

cpu.sh

# !/bin/bash
while :; do
    # grab process id for given arg
    PID=$(ps aux | grep $1 | grep -v grep | grep -v cpu.sh | awk '{print $2}')
    # grab cpu usage
    USED=$(ps -p $PID -o %cpu)
    # grab arg string length + 9
    LEN=$(expr $(echo $1 | awk '{print length}') + 9)
    # hack! print backspace mulitple times to erase previous input
    for (( i=1 ; i<=$LEN ; i++ )); do
        echo \\b\\c;
    done
    # echo cpu usage
    echo $1 $USED\\c
done