Shell Programming and Scripting

I have a script which uses READ to detect choice of menu option...now I want to change the script without doing whole rewrite such that when user runs ./script.sh 5 it would execute menu option 5 rather than user running ./script.sh waiting for it to load and then pressing "5 enter"

Is it possible to keep both functionalities (user can select from menu if no variable is passed or user can pass option upon running)....


Thanks!

Yes, it is possible:

Code:

ans=$1
while [[ -z $ans ]]
do
    read ans
done

case $ans in
    1)  echo one;;
    5)  echo five;;
    *)  echo "not a valid option: $ans"
esac