While using usertools/dpdk-setup.sh if the user enters any non-alphanumeric character, by mistake perhaps, instead of giving an error and allowing user to re-enter his choice, the dpdk-setup script crashes giving the following message:

./dpdk-setup.sh: line 598: >: syntax error: operand expected (error token is ">")

A possible solution can be to put a conditional statement before the execution of line 598 which is:
${OPTIONS[our_entry]} ${our_entry}
To make sure this statement is only executed when the input is correct.

This error can be replicated easily by following these steps:
1. Enter these commands on the terminal
cd dpdk/usertools
./dpdk-setup.sh
2. When prompted, enter any non-alphanumeric character such as ">"