To display the print queue for your default printer:
lpstat Rank Owner Job Files active joe 483 overheads.ps 2nd sarah 484 /tmp/RFC137 3rd tony 485 report
This displays the print queue for your default printer: the one defined by your PRINTER environment variable.
Each job in the queue has a job number. Details are also given about the job's position in the queue and the user's name.
To display the print queue for a specific printer:
lpstat -dpsmath
This displays the print queue for the printer psmath.