You don't necessarily have to use those, you could just save it to a file in MyDocs first: Code: echo root:$(grep -A 13 lock_code /dev/mtd1|tail -1): > /home/user/MyDocs/old_lockcode Then use the usb cable and copy the file old_lockcode from the device and invoke john the ripper on it as instructed. You could also simply copy&paste the code to pastebin.com or such with the n900 and then copy&paste it again to a file on a computer to avoid messing with the cable.
echo root:$(grep -A 13 lock_code /dev/mtd1|tail -1): > /home/user/MyDocs/old_lockcode