您需要一个时循环和这样的布尔变量:
flag = true
while [ $flag ]; do
case $ans in
1) echo "Running Project 1..."
sleep 2
./project1.sh
;;
2) echo "Running Project 2..."
sleep 2
./project2.sh
;;
Qq) echo "Exiting"
flag = false
;;
esac
done