$ cd $TOSDIR/../apps/tests/TestPrintf
$ make telosb
- $ java PrintfClient -comm serial@/dev/ttyUSBXXX:telosb
+ $ java net.tinyos.tools.PrintfClient -comm serial@/dev/ttyUSB0:telosb
(http://docs.tinyos.net/ has a section on how to use the TinyOS printf library)