Print command is not executed. This problem occurs both in the Slackware packages and when compiled from source
Jobs sent to printers are process by CUPS, bypassing the defined print command. When the command:
lp -H hold -d %p %s
did not work, I created a script that copied the command line used to a file and replaced "lp" in the above setting with my script. The script was never executed. Jobs were sent directly to CUPS.
Setting you "printing" option to BSD should resolve this.
Please reopen if not.