The default print command for many of the hard copy drivers is a call to the script ``wr_lp''. This script is located in the same directory as the program binaries, and can be customized by the (super) user. The script is a wrapper around the system printer command (usually ``lpr'') and is designed to solve a problem. The application will not delete temporary files created for printing/plotting, since there is no way generally for the application to know when the job is finished and it is safe to delete the file. The wr_lp script runs the UNIX ``at'' command, which will delete the file one hour after the print job is submitted. This is true whether or not the application is running, or if the user is no longer logged in. See the manual page for the at command to make sure that it is set up correctly.
Some versions of the lpr command provide a ``-r'' option, which will remove the file when printing is complete (see ``man lpr''). Use of this option is an alternative to using the wr_lp script.