Basic Printing on OpenBSD

Brother Network Printer with PostScript

I have a roughly ten year old Brother HL-5370DW printer on the shelf next to me. This printer is mostly used by my wife to print sewing patterns. When I was studying computer science, I sometimes printed documents I’ve written for proofreading. I often was able to find typos that I didn’t see on the screen even after proofreading the document two or three times. However, I didn’t bother to print out my bachelor thesis. Printing 120 pages just for proofreading just seemed a waste to me. I did my proofreading on the screen extra carefully, and nobody complained about typos. (Which doesn’t mean that there were none.)

Having finished my studies, I hardly ever print out documents. However, I still prefer to read long texts on paper rather than on the screen. Therefore I often buy technical books as paperbacks or hardcovers rather than ebooks. And if I buy an ebook with demanding content, I print out those sections for offline reading.

Having switched to OpenBSD for my private computing shifted my reading habits more towards manpages. When I need to figure out how something works on OpenBSD, apropos(1) beats Google as a starting point in many cases. Some manpages are really long, for example ksh(1). I have a book on the Korn Shell in my basement, which covers ksh93. However, there are some differences between ksh93 and OpenBSD’s pdksh. So reading the manpage not only gives me more accurate information, but also less to read.

So why not printing out the manpage ksh(1)? I can do so even nicely formatted using PostScript:

$ man -T ps -O paper=a4 ksh >ksh.1.ps

Now ksh.1.ps can be read with zathura(1), given that the package zathura-ps is installed:

# pkg_add zathura zathura-ps
$ zathura ksh.1.ps

But why using PostScript and not PDF like anybody else for the last twenty five years? Because PostScript is the least common denominator and, thus, supported out of the box by OpenBSD. (For fancier printing options, check out cups, but I’d like to keep it minimalistic for the moment.)

Printer Setup

I figured out how to configure my printer by reading the section The lpd Printing Daemon in the 16th chapter of Absolute OpenBSD (2nd Edition) (p. 306-307) by Michael W Lucas. This is how I applied the configuration to my local setup.

First, I created the file /etc/printcap with the following content:

lp|brother:\
    :sh=:\
    :rm=192.168.178.52:\
    :sd=/var/spool/output/brother:\
    :lf=/var/log/lpd-errs:\
    :rp=brother

There must be a newline at the end of the file. The line breaks are escaped using backslashes, except for the last line. The options are defined as follows:

• The first line defines two names for my printer: lp, which should always be there, and brother, which is my arbitrary name for the printer.
• The second line (sh) defines that no burst page (summarizing the last print job on a special page) should be printed.
• The third line (rm) refers to the printer on the network. My FritzBox always gives the same IP to my printer. It’s also possible to use the printer’s hostname.
• The fourth line (sd) defines the spooler directory for this printer. Print jobs are written into that directory.
• The fifth line (lf) defines a log file for error messages, which you hopefully never need to check.
• The sixth line (rp) defines the remote printer name.

Next, the spooler directory needs to be created. It must be owned by the user root and the group daemon. Regular users need write access to this directory in order to print documents:

# mkdir /var/spool/output/brother
# chown -R root:daemon /var/spool/output/brother
# chmod 770 /var/spool/output/brother

Now the printer daemon lpd needs to be activated. To do so on system startup, add the following line to /etc/rc.conf/local:

lpd_flags=""

Then start the service:

# /etc/rc.d/lpd restart

Update (2020-09-21): As one reader on Hacker News pointed out, the last two steps can be performed using rcctl(8):

# rcctl enable lpd
# rcctl restart lpd

The manpage says that rcctl(8) was introduced in OpenBSD 5.7 back in 2015. Absolute OpenBSD (2nd Edition) is from 2013 and, thus, older than that. (At the time of this writing, I’m using Version 6.7.)

Another reader pointed out that setting the access rights to 777 is a bad practice. That’s true, and I actually got the reasoning behind this wrong: I thought any user must be able to write to the spooler, because any user is supposed to print. However, it’s lpd that is writing to the spooler, which of course runs under the daemon group. Therefore, the access rights for /var/spool/output/brother should be set to 770, not to 777 (as corrected above).

Printing Documents

Now the printer is ready to accept jobs. In order to print the PostScript file generated before, just run lpr on the file:

$ lpr ksh.1.ps

It’s also possible to send the PostScript output directly to the printer (this is Unix, after all), if no preview is needed:

$ man -T ps -O paper=a4 ksh | lpr

Printing plain text files behaved strange on my setup, but it worked well using the pr formatter with lpr as follows:

$ lpr -p plain.txt

Instead, I also convert plain text files to PostScript, which looks quite nice on paper. I use enscript(1) for this task:

# pkg_add enscript
$ enscript plain.txt -o plain.ps
$ lpr plain.ps

PDFs can also be converted to PostScript using pdf2ps(1), which comes with GhostScript, i.e. the ghostscript package:

$ pdf2ps document.pdf document.ps

Unfortunately, this doesn’t work with all PDFs. But for the time being, I have enough manpages to read. Printing PostScript works extremely fast, by the way. When I press return at the end of a lpr command, I can see the status LED on my printer start blinking almost immediately.