Linux substring & if

1#!/bin/bash -x
2. $HOME/.bash_profile
3var=POJ_2 
4versionNumber=${var:4:1} 
5 if [ "$versionNumber" = "1" ]; then 
6    echo "Project 1"
7elif [ "$versionNumber" = "2" ]; then
8    echo "Project 3"
9else
10 echo "sorry I don't know!"
11 exit 0
12fi