Shell Programming and Scripting

Hi there, if i have a simple getopts like below ...how can i make it so that if somebody enters more than one -g argument for example, it will error with a " you cannot enter more than one -g" or something like that.?

I want to only allow one instance of a -g or a -h etc ..

Code:

while getopts :g:h: var
do
   case $var
   in
       g) echo " g = $OPTARG" ;;
       h) echo "h = $OPTARG" ;;
       :) echo "Illegal option: $OPTARG"
          echo "$usage"
   esac
done

does anybody know how i would do this ... i want to stop people entering

Code:

# script.sh -g peter -g paul -g john

any help on this would be greatly appreciated

Hi.

Set a variable as a flag that an option has already been specified, check the flag at the appropriate case selector, issue message if it has been set, set it if it hasn't ... cheers, drl