A text browser with links --dump

This browser implemets quit (q) , back (b) and url.And a hidden command called 'd' which dumps history.More importantly i use the bash arrays.On L.H.S its HISTORY[$i] where as on R.H.S its ${HISTORY[$i]} and the length of array is ${#HISTORY[@]}...

#!/bin/bash
HISTORY=()
BACKINDEX=0

function updatehistory() {
    numvalues=${#HISTORY[@]}
    if (( $numvalues < 3 ))
        then
            HISTORY[$numvalues]=$1
        else
                    index=$(( numvalues -1))
            for (( i=0;i<$index;i++))
            do
                         j=$(( i+1))
                     HISTORY[$i]=${HISTORY[$j]}
                    done
                    i=$(( i++))
                HISTORY[$i]=$1
            fi
}



function dump_history(){

numvalues=${#HISTORY[@]}

        for (( i=0; i < $numvalues; i++))
        do
                    echo ${HISTORY[$i]}
        done
  }

while true
do
        echo "Enter a url.q for quit and b for back"
        read choice

        case $choice in

            q) exit ;;

            b) BACKINDEX=$(( BACKINDEX+1))
            numvalues=${#HISTORY[@]}
              INDEX=$(( numvalues - BACKINDEX -1 ))
              links  -http-proxy proxyserver:8088  -dump ${HISTORY[$INDEX]}
              ;;

            d) dump_history;;

            *) links  -http-proxy proxyserver:8088  -dump $choice
                        if ((  $? == 0 ))
                then
                    updatehistory $choice
                        fi
                        BACKINDEX=0
                        ;;
        esac

done