Originally Posted by duckduckgoose

If i'm not mistaken, the 30 alone means it will run at :30 of every hour, day, etc. His intention seems originally to run it every half hour, meaning at :00 and :30.

also, the message "bad interpreter: No such file or directory" in this situation usually means you don't have that shell installed. Try putting /bin/bash instead and see if it runs manually then. Some systems just don't have the original Bourne shell installed anymore.