Andrew Hudson - Fedora™ Unleashed, 2008 edition

# lprm 7

The lprmcommand removes the spooled files from the printer's queue and kills the job. Print job owners, such as regular users, can remove only spooled jobs that they own. As the root operator, you can kill any job.

Only the root operator can use the lpccommand to administer printers and queues because the command is primarily used for printer and queue control. You, as a regular user, cannot use it to rearrange the order of your print jobs, but you can get a display of the status of any system printer. Start lpcon the command line like this:

# /usr/sbin/lpc

The lpccommand has built-in help, but it consists of only five commands: exit, help, quit, status, and ?. The statuscommand shows the status of a specified printer or all printers:

# lpc

lpc> ?

Commands may be abbreviated. Commands are:

exit help quit status ?

lpc> status

lp:

printer is on device 'parallel' speed -1

queuing is enabled

printing is enabled

no entries

daemon present

netlp:

printer is on device 'parallel' speed -1

queuing is enabled

printing is enabled

no entries

daemon present

lpc> quit

The preceding sample session shows a status report for two printers: lp and netlp. Another helpful command is lpstat, which you use like this with its -toption:

# lpstat -t

scheduler is running

system default destination: lp

device for lp: parallel:/dev/lp0

device for netlp: parallel:/dev/lp0

lp accepting requests since Jan 01 00:00

netlp accepting requests since Jan 01 00:00

printer lp is idle. enabled since Jan 01 00:00

printer netlp is idle. enabled since Jan 01 00:00!)

This command lists all status information about printer queues on the local system.

Troubleshooting printer problems can be frustrating, especially if you find that your new printer is not working properly with Linux. First, keep in mind that nearly all printers on the market today work with Linux. However, some vendors have higher batting averages in the game of supporting Linux. If you care to see a scorecard, browse to http://www.linuxprinting.org/vendors.html.

Problematic printers, or printing devices that might or might not work with Fedora, include multifunction (or all-in-one ) printers that combine scanning, faxing, and printing services. You should research any planned purchase, and avoid any vendor unwilling to support Linux with drivers or development information.

One shining star in the field of Linux support for multifunction printers is the HP support of the HP OfficeJet Linux driver project at http://hpoj.sourceforge.net/. Printing and scanning are supported on many models, with fax support in development.

Other problems can arise from the lack of a printer's USB vendor and device ID information — a problem shared by some USB scanners under Linux. For information regarding USB printer support, you can check with the Linux printing folks (http://www.linuxprinting.org/vendors.html) or with the Linux USB project athttp://www.linux-usb.org/.

Although many newer printers require a universal serial bus (USB) port, excellent support still exists for legacy parallel-port (IEEE-1284) printers with Linux, enabling sites to continue to use older hardware. You can take advantage of Linux workarounds to set up printing even if the host computer does not have a traditional parallel printer port or if you want to use a newer USB printer on an older computer.

For example, to host a parallel port-based printer on a USB-only computer, attach the printer to the computer using an inexpensive USB-to-parallel converter. USB-to-parallel converters typically provide a Centronics connector; one end of that connector is plugged in to the older printer, whereas the other end is plugged in to a USB connector. The USB connector is then plugged in to your hub, desktop, or notebook USB port. On the other hand, you can use an add-on PCI card to add USB support for printing (and other devices) if the legacy computer does not have a built-in USB port. Most PCI USB interface cards add at least two ports, and devices can be chained via a hub.

Related Fedora and Linux Commands

► accept — Controls print job access to the CUPS server via the command line

► cancel — Cancels a print job from the command line

► disable — Controls printing from the command line

► enable — Controls CUPS printers

► lp — Sends a specified file to the printer and allows control of the print service

► lpc — Displays the status of printers and print service at the console

► lpq — Views print queues (pending print jobs) at the console

► lprm — Removes print jobs from the print queue via the command line

► lpstat — Displays printer and server status

► system-config-printer — Displays Fedora's graphical printer configuration tool

► system-config-printer-tui — Displays Fedora's text-dialog printer configuration tool

► http://www.linuxprinting.org/— Browse here for specific drivers and information about USB and other types of printers.

► http://www.hp.com/wwsolutions/linux/products/printing_imaging/index.html— Short but definitive information from HP regarding printing product support under Linux.

► http://www.cups.org/— A comprehensive repository of CUPS software, including versions for Red Hat Linux.

► http://www.pwg.org/ipp/— Home page for the Internet Printing Protocol standards.

► http://www.linuxprinting.org/cups-doc.html— Information about CUPS.

► http://www.cs.wisc.edu/~ghost/— Home page for the Ghostscript interpreter.

► http://www.samba.org/— Base entry point for getting more information about Samba and using the SMB protocol with Linux, UNIX, Mac OS, and other operating systems.

► In addition, an excellent book on Samba to help you learn more is Using Samba, 3rd Edition (O'Reilly & Associates, ISBN: 0-596-00769-8).

File Transfer Protocol (FTP) was once considered the primary method used to transfer files over a network from computer to computer. FTP is still heavily used today, although many graphical FTP clients now supplement the original text-based interface command. As computers have evolved, so has FTP, and Fedora includes many ways with which to use a graphical interface to transfer files over FTP.