Dear Mr. Matti Kurkela,
Thanks for your quickly reply.
I wonder that, which "<printerhost> [port] " should I put in the shell script command. In my scenario, I plug my HP Printer in these usb 2.0 ports and directly connect with my Computer via usb cable (the printer is not network printer).
So, may I run it with the command:
$sh pjl-get-serial.sh localhost 9100
or
$sh pjl-get-serial.sh 127.0.0.1 9100
PS: How can I check as if the port 9100 is correct with my printer service?