The point is, look at the difference between that and your code. The point isn't "do you have bash on your N900". I don't either.
Nokia-N900-02-8:/etc/network# vi detectUsb.test.sh #!/bin/sh my="abcd" if [[ $my = *bc* ]] then echo "Ok" else echo "Not ok" fi ~ ~ Nokia-N900-02-8:/etc/network# ./detectUsb.test.sh Not ok Nokia-N900-02-8:/etc/network#