COPY program.ps printer
Where "printer" indicates the parallel printer port ( LPT1,LPT2, LPT3, PRN ) that the printer is attached.
lpr program.ps
if the printer you want to print that file on is the default printer, and:
lpr -P printername program.ps
where "printername" is a name of the Post Script printer on your system. If your UNIX system does not have "lpr" command or you not sure if you can print Post Script files on it, ask you system administrator to help you.