To run a foreground process as a background job:
1. Suspend the foreground process.
2. Enter the bg (background) command to move the process into the background.
lpr -Pps23 part[1-8].ps ^Z Stoppped bg  lpr -Pps23 interface.ps & jobs  Running lpr -Ppsa interface.ps
This starts a foreground process to print several files. The process is then stopped and the job moved into the background. The state of this job is then checked.