[SOLVED] How do I send a plain ASCII file to the printer?

stf92 · 12-07-2013, 11:29 PM

Hi: I run a GNU linux operating system (Slackware 14.0). The problem consists in using the parallel port to get into the Centronics connector of my dot matrix printer and print a plain ASCII file in the printer. But we could make the problem simpler: output redirection to the parallel printer port.

I know this: with an old linux O.S. I did

Code:

$ ls > /dev/lp0

and I got printer output. That's all I needed. But there is no /dev/lp0 device on my O.S.! What are the parallel printer devices in linux now?

As the printer is programmable, I could make a file with the appropriate control characters and then

Code:

cat control_chars_file > /dev/<printer_device>

A more comfortable scenario would be to write a C program and send the control characters and text to the printer via suitable output instructions. But here I would need to know the proper output instructions, which I do not know.

[I know: I would use the int fprintf(FILE *stream, const char *format, ...) instruction after having associated some output stream with the printer device.]

allend · 12-08-2013, 12:07 AM

If you have the printer configured in CUPS, then

Code:

lpr -P <printer_name> <ASCII_filename>

stf92 · 12-08-2013, 12:24 AM

Oh, but I would much rather prefer to get a more straightforward connection to the printer, without queues and all that. I only need the name of the device.

allend · 12-08-2013, 02:21 AM

Perhaps 'dmesg | grep lp' will help.

gnashley · 12-08-2013, 04:18 AM

Have you looked into pdq -Print Don't Queue?

stf92 · 12-08-2013, 05:26 AM

I have just remembered this machine lacks a parallel port connector. The manufacturer of the machine or of the relevant chipset must have thought a parallel port had no object in a world where everything is USB. By the same criteria, sure enough, he did not provide a serial RS232 port. So udev did not create the corresponding device, despite the fact that the driver is there:

Code:

ppdev: user-space parallel port driver
lp: driver loaded but no devices found

(from dmesg output)

Code:

lp                      9787  0 
parport                31427  3 parport_pc,ppdev,lp

(from lsmod output)

What the manufacturer does not considered is that parallel and serial (UART) ports are infinitely simpler than USB devices, and make the life of some persons much simpler. That is, USB appeared as an attempt to simplify the life of the housewife and the butcher and the architect that is, keeping in mind the innumerable types of people who at present use a computer. The computer should be usable by a three-year old kid. A pity, in this way they fabulously complicated mine. udev is another of those smart inventions aimed at easing the life of the end user at the cost of infinitely complicating computers themselves.

What I forgot is that I use another computer to test (mostly homebrew) parallel devices and was using this only to see how the /dev/lp thing was done. Sorry to have bothered you, guys.