OK, this exercise should be a bit trickier -- given a character MAC address, how can I break it into individual hex chars for writing to EEPROM? So the script takes the argument, say, "A0:B1:C2:D3:E4:F5", and I need to, one nibble at a time, get the value 0x0A, 0x0, 0x0B, 0x01 and so on. (Doesn't matter if the invoker wants to put the colons in or not, I can just run the string through "tr -d ':'" to deal with that.) As earlier, I can always loop through each character in the MAC address, but I'm wondering if there's some clever "printf" format that can do that all at once. rday