NAME
printcap —
printer capability data base
SYNOPSIS
printcap |
DESCRIPTION
The printcap function is a simplified
version of the
termcap(5) data base used to describe line printers. The spooling
system accesses the printcap file every time it is
used, allowing dynamic addition and deletion of printers. Each entry in the
data base is used to describe one printer. This data base may not be
substituted for, as is possible for
termcap, because it may
allow accounting to be bypassed.
The default printer is normally lp, though the
environment variable PRINTER may be used to override
this. Each spooling utility supports an option, -P
printer, to allow explicit naming of a destination
printer.
Refer to the 4.3 BSD Line Printer Spooler Manual for a complete discussion on how to setup the database for a given printer.
CAPABILITIES
Refer to termcap(5) for a description of the file layout.
| Name | Type | Description | |
| af | str | NULL |
name of accounting file |
| br | num | none | if lp is a tty, set the baud rate (ioctl(2) call) |
| cf | str | NULL |
cifplot data filter |
| df | str | NULL |
tex data filter (DVI format) |
| fc | num | 0 | if lp is a tty, clear flag bits (sgtty.h) |
| ff | str | ‘\f’ |
string to send for a form feed |
| fo | bool | false | print a form feed when device is opened |
| fs | num | 0 | like `fc' but set bits |
| gf | str | NULL |
graph data filter (plot(3) format |
| hl | bool | false | print the burst header page last |
| ic | bool | false | driver supports (non standard) ioctl to indent printout |
| if | str | NULL |
name of text filter which does accounting |
| lf | str | /dev/console | error logging file name |
| lo | str | lock | name of lock file |
| lp | str | /dev/lp | device name to open for output |
| mx | num | 1000 | maximum file size (in BUFSIZ blocks), zero =
unlimited |
| nd | str | NULL |
next directory for list of queues (unimplemented) |
| nf | str | NULL |
ditroff data filter (device independent troff) |
| of | str | NULL |
name of output filtering program |
| pc | num | 200 | price per foot or page in hundredths of cents |
| pl | num | 66 | page length (in lines) |
| pw | num | 132 | page width (in characters) |
| px | num | 0 | page width in pixels (horizontal) |
| py | num | 0 | page length in pixels (vertical) |
| rf | str | NULL |
filter for printing FORTRAN style text files |
| rg | str | NULL |
restricted group. Only members of group allowed access |
| rm | str | NULL |
machine name for remote printer |
| rp | str | ``lp'' | remote printer name argument |
| rs | bool | false | restrict remote users to those with local accounts |
| rw | bool | false | open the printer device for reading and writing |
| sb | bool | false | short banner (one line only) |
| sc | bool | false | suppress multiple copies |
| sd | str | /var/spool/lpd | spool directory |
| sf | bool | false | suppress form feeds |
| sh | bool | false | suppress printing of burst page header |
| st | str | status | status file name |
| tf | str | NULL |
troff data filter (cat phototypesetter) |
| tr | str | NULL |
trailer string to print when queue empties |
| vf | str | NULL |
raster image filter |
| xc | num | 0 | if lp is a tty, clear local mode bits (tty(4)) |
| xs | num | 0 | like `xc' but set bits |
If the local line printer driver supports indentation, the daemon must understand how to invoke it.
The lp entry can specify either a device in the ``/dev'' directory or a printer accessible via the network using the syntax:
:lp=port
@host
printcap:where host is the network name of the printer and port is the TCP port number to use for the network connection. This works both for printers directly connected to the network (and which understand TCP/IP) as well as for many terminal servers that support printers via their serial and/or parallel ports.
FILTERS
The lpd(8) daemon creates a pipeline of filters to process files for various printer types. The filters selected depend on the flags passed to lpr(1). The pipeline set up is:
p pr | if regular text + pr(1) none if regular text c cf cifplot d df DVI (tex) g gf plot(3) n nf ditroff f rf Fortran t tf troff v vf raster image
The if filter is invoked with arguments:
if
[-c]
-wwidth
-llength
-iindent
-n login
-h host acct-fileThe -c flag is passed only if the
-l flag (pass control characters literally) is
specified to lpr. The
width function and length
specify the page width and length (from pw and
pl respectively) in characters. The
-n and -h parameters specify
the login name and host name of the owner of the job respectively. The
Acct-file function is passed from the
af printcap entry.
If no if is specified,
of is used instead, with the distinction that
of is opened only once, while
if is opened for every individual job. Thus,
if is better suited to performing accounting. The
of is only given the width and
length flags.
All other filters are called as:
filter
-xwidth
-ylength
-n login
-h host acct-filewhere width and length
are represented in pixels, specified by the px and
py entries respectively.
All filters take
stdin as the file,
stdout
as the printer, may log either to stderr or using
syslog(3), and must not ignore SIGINT.
LOGGING
Error messages generated by the line printer programs themselves
(that is, the lp* programs) are
logged by syslog(3) using the LPR facility.
Messages printed on stderr of one of the filters are sent
to the corresponding lf file. The filters may, of
course, use syslog
themselves.
Error messages sent to the console have a carriage return and a line feed appended to them, rather than just a line feed.
ADMINISTRATION
In a networked environment with many hosts, it is convenient to
use the same printcap file on all machines. This is
accomplished by specifying the complete set of entries for every printer on
all machines, including entries for both the rm and
lp capabilities. This is possible because the
lpd daemon matches the
rm printcap entry with the local host name and only
opens the line printer specified by lp if the names
match. Otherwise the lp entry is ignored and the
spooled file is sent on to the remote machine for printing.
SEE ALSO
termcap(5), lpc(8), lpd(8), pac(8), lpr(1), lpq(1), lprm(1)
4.3 BSD Line Printer Spooler Manual.
HISTORY
The printcap file format appeared in
4.2BSD.