Shell Programming and Scripting

count_collatz_step() {
   step=0
   num=$1
   while [ $num -ne 1 ]
   do
    if [ $((num % 2)) -eq 0 ]
    then
        num=$((num/2))
        step=$((step + 1))
    else
        num=$((3*num+1))
        step=$((step + 1))
    fi
   done
   echo $step
}

echo "Input start point: "
read start
echo "Input end point: "
read end

count=0

while [ $start -lt $end ]
do
    echo $start + ":" + $(count_collatz_step $start)
    if [ $((count % 7)) -eq 0 ]
    then
        echo -e "\n"
    fi
    start=$((start+1))
    count=$((count+1))
done