bash case statement with unmatched patterns

Question

Ok, so i have tried searching for this on google and i cant seem to find an answer. What i'm trying to do is create a case statement in bash but if the user enters a different number than listed it just exits the script. How do i make it give an error and then ask for the user to select one of the options?

for example, my case statement

case $ans in
1) echo "Running Project 1..."
   sleep 2
   ./project1.sh
;;
2) echo "Running Project 2..."
   sleep 2
   ./project2.sh
;;
Qq) echo "Exiting"
    exit
;;
esac

so any options other than 1, 2, Qq it will give an error saying invalid selection, try again.

I just tried wrapping an if statement around case statment and it still doesn't work, maybe my if statement is wrong? if [ $ans == "1" || $ans == "2" || $ans == "q" || $ans == "Q" ] — Zedd Almighty
– Zedd Almighty, Commented Dec 3, 2013 at 14:21
You might also want to take a look at the select statement. — chepner
– chepner, Commented Dec 3, 2013 at 14:40

wannaKnowItAll · Accepted Answer · 2013-12-03 14:19:45Z

1

You need a while loop and a boolean variable like that:

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

answered Dec 3, 2013 at 14:19

wannaKnowItAll

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4 Comments

Zedd Almighty Over a year ago

initially this did not work for me but then i moved my read statment for $ans inside the loop and it works. However, the when i try to quit the Qq no longer works. but if i take one q out the other works. Without creating a 4th case option, how do i keep it to its Q or q ?

Zedd Almighty Over a year ago

I'm not sure if this is the proper way or not but i changed Qq) to Q|q) and it seems to work just fine.

wannaKnowItAll Over a year ago

Yes, you are right as you can see here the syntax of OR between two patterns

Zedd Almighty Over a year ago

also i changed the while loop around a bit. First for the Q|q) choice instead of having it exit from that choice i had it set the flag to false. In the while loop i changed it to while [ $flag = "true" ];do instead, so once the exit choice is selected it changes the value to false and the loop exits. This way allows me to run more commands if i need to.

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