Shell : getopts option with two argument would stop the script

Question

I had make a script called test.sh look like below

while getopts a:b: opt
do
  case $opt in
    a) a1=$OPTARG
       ;;
    b) b1=$OPTARG    
       eval "b2=\${$OPTIND}"
       shift 2;;   

  esac
done

echo $a1;
echo $b1;
echo $b2;

When I try the command below, its work...

test.sh -a 111 -b 222 333

111
222
333

But if I try this one...

test.sh -b 222 333 -a 111 

222
333

It only can display -b argument, -a option and agrument can not work after -b option...

any problem at my script???? thank you :)

Answer 1

Modifying argument indexes with shift 2 does not play along with getopts. Instead you should increment OPTIND by one to get getopts to skip the next argument, e.g something like

while getopts a:b: opt
do
        case $opt in
                a) a1=$OPTARG
                        ;;
                b) b1=$OPTARG    
                        eval "b2=\${$OPTIND}"
                        OPTIND=`echo $OPTIND + 1 | bc`
                        ;;
        esac
done

echo $a1;
echo $b1;
echo $b2;