Best of Technical Support

Our experts answer your technical questions.
Printer Won't

I am running Red Hat 7.2 and trying to install my HP DeskJet 932C. I have done everything by the book, even tried all the drivers listed, and the printer still does not work. Can anyone tell me what the deal is here? Yes, it is a USB printer.

—Tim Fey,

Try modprobe printer, and check out /var/log/messages to see if your printer is detected. You can then use printtool to configure it for use with your distribution.

—Christopher Wingert,

Try another USB device to make sure the port you are using with the printer is working. If you are getting any error messages please send them.

—Don Marti,

You do not say if you're having a problem configuring the USB to talk to the printer or a problem with the actual data format sent to the printer with a working USB connection. If it's the latter, I'd suggest you go to CUPS for the latest drivers for your printer, You can even generate the proper configuration files for your printer on-line.

—Felipe Barousse Boué,

Don't Run This Program Twice

In libc is there a function to call to see if my application is already running?

—Pieter Coetzee,

The way most programs do this is they store their PID in a file such as /var/run/

—Marc Merlin,

/var/run is writable only by root. If you want to have only one copy of an X application running per user, gnome-moz-remote probably does something close to what you want. It looks for an already running copy of Mozilla, and if one is running, it opens the given URL with that copy. Otherwise, it starts a new Mozilla process. Look at

—Don Marti,