UNIX for Dummies Questions & Answers

Wrote the following loop to but if I use exit, then I break entirely from my script, but instead I want to break from the case/esac and go to the next line in my script. I guess I need to know how to exit gracefully from a "while (true). Also, how can I allow the user to enter upper or lowercase as valid responses. An "A", will be treated the same as an "a", without replicating logic?

Code:

while (true)
do
  echo "  a b c "   
  echo " Enter one of the environments from above: \c"
  read reply
   case $reply in
      a)  echo a is valid & exit  ;;        
      b)  echo b is valid & exit ;;
      c)  echo c is valid & exit ;;
      *)  echo $reply is not valid - try again
   esac
done

Change your "exit" statements within each case to break. For the upper case/lower case, its easier to allow the user to enter either but allow your script to evaluate only 1. You can do this by typing your variable reply as either uppercase or lowercase using the typeset command. Outside of the while loop, you may break out of the loop by either changing the condition that you are using to loop or by using another break command.

Example.

typeset -u reply (this will cause the input to be shifted to upper case. So when the user enters 'a', the script reads 'A'). typeset -l is the complement to the -u flag. It changes things to lower case.

Be sure to change your case statement accordingly to match for either upper or lower case.

I have a query on this break. I am using a program where I am using a while loop to execute it. It will get into a file take the first file and then ping it and if the ip is reachable then it will mail. Now what happens is that when i ping the ip it does nopt come out of the loop and it says "reply from reply from" . I need to usse a break statemetn to come out of this. Can you assist me in this.

Sounds like you just have to change your ping command. Try using 'ping -c 1 <some_host>'. That will try to ping only once instead of constantly.

HTH

What about when exiting from a loop and a case? such like...

Code:

case $CASE in
1)

2)
   while ps $PID
   do
      if [ $? -eq 0 ];then
         echo "exit from this while loop and exit from case, how will I do that?"
      fi
   do

3)

...

esac