UNIX for Dummies Questions & Answers

I am trying to setup an if, elif statement that is dependant on a variable. If the user does not enter a valid option I would like it to prompt them again and start the loop over. Here is what I have so far:


echo -n "enter variable (a, b, or c): "
read freq

if [ $freq = a ];
then echo "a"
elif [ $freq = b ];
then echo "b"
elif [ $freq = c ];
then echo "oh my god the world is going to end"
else echo -n "The only options are a, b, or c. Please try again: " < - this is where I want it to start over again.


fi

thanks

Code:

#!/bin/sh

echo -n "enter variable (a, b, or c): "
read freq

until [ "$freq" = "a" ] || [ "$freq" = "b" ] || [ "$freq" = "c" ]; do
        echo -n "The only options are a, b, or c. Please try again: "
        read freq
done

if [ $freq = a ]; then
        echo "a"
elif [ $freq = b ]; then         
        echo "b"
elif [ $freq = c ];then
        echo "oh my god the world is going to end"
fi

Thank you very much. Works like a charm