Restart Printer Services

Restart Printer Services if printer can't print but printer status is ready (ubuntu with non HP Printer)

1. Type sudo /etc/init.d/cupsys restart
2. Your Printer will resume its job

Print plain text file without printer driver to improve speed dot matrix printer (ubuntu)

1. Set permision /dev/lp0 (LPT Device) to readwrite by other user by type sudo chmod 666 /dev/lp0
2. To print plain text file, type cp /dev/lp0