Typical FreeBSD text files contain only a single line feed character at the end of each line. These lines will “stairstep” on a standard printer:

A printed file looks
                    like the steps of a staircase
                                                 scattered by the wind

A filter can convert the newline characters into carriage returns and newlines. The carriage returns make the printer return to the left after each line. Create /usr/local/libexec/lf2crlf with these contents:

#!/bin/sh
CR=$'\r'
/usr/bin/sed -e "s/$/${CR}/g"

Set the permissions and make it executable:

# chmod 555 /usr/local/libexec/lf2crlf

Modify /etc/printcap to use the new filter:

:if=/usr/local/libexec/lf2crlf:\

Test the filter by printing the same plain text file. The carriage returns will cause each line to start at the left side of the page.

GNU Enscript converts plain text files into nicely-formatted PostScript® for printing on PostScript® printers. It adds page numbers, wraps long lines, and provides numerous other features to make printed text files easier to read. Depending on the local paper size, install either print/enscript-letter or print/enscript-a4 from the Ports Collection.

Create /usr/local/libexec/enscript with these contents:

#!/bin/sh
/usr/local/bin/enscript -o -

Set the permissions and make it executable:

# chmod 555 /usr/local/libexec/enscript

Modify /etc/printcap to use the new filter:

:if=/usr/local/libexec/enscript:\

Test the filter by printing a plain text file.

Many programs produce PostScript® documents. However, inexpensive printers often only understand plain text or PCL. This filter converts PostScript® files to PCL before sending them to the printer.

Install the Ghostscript PostScript® interpreter, print/ghostscript9-base, from the Ports Collection.

Create /usr/local/libexec/ps2pcl with these contents:

#!/bin/sh
/usr/local/bin/gs -dSAFER -dNOPAUSE -dBATCH -q -sDEVICE=ljet4 -sOutputFile=- -

Set the permissions and make it executable:

# chmod 555 /usr/local/libexec/ps2pcl

PostScript® input sent to this script will be rendered and converted to PCL before being sent on to the printer.

Modify /etc/printcap to use this new input filter:

:if=/usr/local/libexec/ps2pcl:\

Test the filter by sending a small PostScript® program to it:

% printf "%%\!PS \n /Helvetica findfont 18 scalefont setfont \
72 432 moveto (PostScript printing successful.) show showpage \004" | lpr

A filter that detects the type of input and automatically converts it to the correct format for the printer can be very convenient. The first two characters of a PostScript® file are usually %!. A filter can detect those two characters. PostScript® files can be sent on to a PostScript® printer unchanged. Text files can be converted to PostScript® with Enscript as shown earlier. Create /usr/local/libexec/psif with these contents:

#!/bin/sh
#
#  psif - Print PostScript or plain text on a PostScript printer
#
IFS="" read -r first_line
first_two_chars=`expr "$first_line" : '\(..\)'`

case "$first_two_chars" in
%!)
    # %! : PostScript job, print it.
    echo "$first_line" && cat && exit 0
    exit 2
    ;;
*)
    # otherwise, format with enscript
    ( echo "$first_line"; cat ) | /usr/local/bin/enscript -o - && exit 0
    exit 2
    ;;
esac

Set the permissions and make it executable:

# chmod 555 /usr/local/libexec/psif

Modify /etc/printcap to use this new input filter:

:if=/usr/local/libexec/psif:\

Test the filter by printing PostScript® and plain text files.

Writing a filter that detects many different types of input and formats them correctly is challenging. print/apsfilter from the Ports Collection is a smart “magic” filter that detects dozens of file types and automatically converts them to the PDL understood by the printer. See http://www.apsfilter.org for more details.

lpq(1) shows the status of a user's print jobs. Print jobs from other users are not shown.

Show the current user's pending jobs on a single printer:

% lpq -Plp
Rank   Owner      Job  Files                                 Total Size
1st    jsmith     0    (standard input)                      12792 bytes

Show the current user's pending jobs on all printers:

% lpq -a
lp:
Rank   Owner      Job  Files                                 Total Size
1st    jsmith     1    (standard input)                      27320 bytes

laser:
Rank   Owner      Job  Files                                 Total Size
1st    jsmith     287  (standard input)                      22443 bytes

lprm(1) is used to remove print jobs. Normal users are only allowed to remove their own jobs. root can remove any or all jobs.

Remove all pending jobs from a printer:

# lprm -Plp -
dfA002smithy dequeued
cfA002smithy dequeued
dfA003smithy dequeued
cfA003smithy dequeued
dfA004smithy dequeued
cfA004smithy dequeued

Remove a single job from a printer. lpq(1) is used to find the job number.

% lpq
Rank   Owner      Job  Files                                 Total Size
1st    jsmith     5    (standard input)                      12188 bytes
% lprm -Plp 5
dfA005smithy dequeued
cfA005smithy dequeued

lpc(8) is used to check and modify printer status. lpc is followed by a command and an optional printer name. all can be used instead of a specific printer name, and the command will be applied to all printers. Normal users can view status with lpc(8). Only root can use commands which modify printer status.

Show the status of all printers:

% lpc status all
lp:
	queuing is enabled
	printing is enabled
	1 entry in spool area
	printer idle
laser:
	queuing is enabled
	printing is enabled
	1 entry in spool area
	waiting for laser to come up

Prevent a printer from accepting new jobs, then begin accepting new jobs again:

# lpc disable lp
lp:
	queuing disabled
# lpc enable lp
lp:
	queuing enabled

Stop printing, but continue to accept new jobs. Then begin printing again:

# lpc stop lp
lp:
	printing disabled
# lpc start lp
lp:
	printing enabled
	daemon started

Restart a printer after some error condition:

# lpc restart lp
lp:
	no daemon to abort
	printing enabled
	daemon restarted

Turn the print queue off and disable printing, with a message to explain the problem to users:

# lpc down lp Repair parts will arrive on Monday
lp:
	printer and queuing disabled
	status message is now: Repair parts will arrive on Monday

Re-enable a printer that is down:

# lpc up lp
lp:
	printing enabled
	daemon started

See lpc(8) for more commands and options.

The printer name is set in the first line of the entry in /etc/printcap. Additional names, or aliases, can be added after that name. Aliases are separated from the name and each other by vertical bars:

lp|repairsprinter|salesprinter:\

Aliases can be used in place of the printer name. For example, users in the Sales department print to their printer with

% lpr -Psalesprinter sales-report.txt

Users in the Repairs department print to their printer with

% lpr -Prepairsprinter repairs-report.txt

All of the documents print on that single printer. When the Sales department grows enough to need their own printer, the alias can be removed from the shared printer entry and used as the name of a new printer. Users in both departments continue to use the same commands, but the Sales documents are sent to the new printer.

It can be difficult for users to locate their documents in the stack of pages produced by a busy shared printer. Header pages were created to solve this problem. A header page with the user name and document name is printed before each print job. These pages are also sometimes called banner or separator pages.

Enabling header pages differs depending on whether the printer is connected directly to the computer with a USB, parallel, or serial cable, or is connected remotely over a network.

Header pages on directly-connected printers are enabled by removing the :sh:\ (Suppress Header) line from the entry in /etc/printcap. These header pages only use line feed characters for new lines. Some printers will need the /usr/share/examples/printing/hpif filter to prevent stairstepped text. The filter configures PCL printers to print both carriage returns and line feeds when a line feed is received.

Header pages for network printers must be configured on the printer itself. Header page entries in /etc/printcap are ignored. Settings are usually available from the printer front panel or a configuration web page accessible with a web browser.