lpd.8

<B>Digital的Unix操作系统VAX 4.2源码</B>

.TH lpd 8
.SH Name
lpd \- line printer daemon
.SH Syntax
.B /usr/lib/lpd
[
.B \-l
] [
.B \-L
.I logfile
] [
.I portnumber
]
.SH Description
.NXR "lpd daemon"
.NXAM "lpr command" "lpd daemon"
.NXS "line printer daemon" "lpd daemon"
.NXA "lpd daemon" "lpc program"
.NXR "lpd daemon" "key characters"
The
.PN lpd
line printer daemon uses the system calls
.PN listen
and
.PN accept ,
to receive requests to print files in the print queue,
transfer files to the spooling area, display the queue, and remove jobs
from the queue.
.PP
The line printer daemon is invoked by the
.PN /etc/rc
command file when the system goes multi-user (normally at system start
up).
The daemon looks at the
.PN /etc/printcap
file to find out about the capabilities of existing printers, and
prints any files that were not printed when the system last stopped
operating.
.PP
The Internet port number used to rendezvous with other processes is
normally obtained with
.PN getservbyname ,
but can be changed by using the \fIportnumber\fR argument.
.PP
Access to the facilities provided by the
.PN lpd
daemon is controlled by only allowing requests from
the machines listed in the
.PN /etc/hosts.equiv
or
.PN /etc/hosts.lpd
files.
The
.PN /etc/hosts.equiv
file is described on the
.PN hosts.equiv(5yp)
reference page.
The
.PN /etc/hosts.lpd
file is a list of names consisting of one host machine name per line.
An * character at the start of any line in
.PN /etc/hosts.lpd
allows print requests from all systems.  The machine names listed in the 
.PN /etc/hosts.equiv
and
.PN /etc/hosts.lpd
files may optionally contain the local BIND domain name.  For
more information on BIND, see the
.I Guide to the BIND/Hesiod Service.
.PP
You can also control access to the
.PN lpd
daemon by specifying the \fBrs\fR capability for
a particular printer in the
.PN printcap
file.
This restricts the printer users to those with accounts on the
machine which the printer is connected to.
.PP
The file
.I lock
in each spool directory is used to prevent multiple daemons from
becoming active simultaneously, and to store information
about the daemon process for
.PN lpr ,
.PN lpq ,
and
.PN lprm .
.PP
After the daemon has successfully set the lock, it scans the directory
for command files with names beginning with 
.I cf .
These files specify names of files which are to be printed and
parameters affecting how the files are printed.
Each line in a command file begins with a key character
to specify what to do with the remainder of the line.
The key characters and their meanings are shown below.
They are listed in the order that they would appear in a command file.
.PP
If a file is to be printed but can not be opened, 
a message will be placed
in the \fIlogfile\fR (by default, the system console).
.PP
The
.PN lpd
daemon uses 
.PN flock
to provide exclusive access to the \fIlock\fR file.
The lock is automatically removed by the kernel when a
.PN lpd
process terminates for any reason.
The lock file contains two lines.
The first is the process id of the daemon and the second is the control
file name of the current job being printed.
The second line is updated for use by
.PN lpq
and
.PN lprm .
.PP
The key characters in the command file and their meanings are as follows:
.IP H\fIhost\fR 1i
Host Name.
Name of the machine where
.PN lpr
was invoked.
.IP P\fIuser\fR 1i
Person.
Login name of the person who invoked
.PN lpr .
This is used to verify ownership by
.PN lprm .
.IP J\fIjob\fR 1i
Job Name.
String to be used for the job name on the banner page.
.IP C\fIclass\fR 1i
Classification.
String to be used for the classification line on the banner page.
.IP L\fIuser\fR 1i
Literal.
The line contains identification information from
the password file and causes the banner page to be printed.
.IP I\fInum\fR 1i
Indent.
The number of characters by which the output is indented (in ASCII).
.IP M\fIuser\fR 1i
Send mail to the specified user when the current print job completes.
.IP 1\fIfont\fR 1i
Troff Font R.
Name of the font file to use instead of the default.
.IP 2\fIfont\fR 1i
Troff Font I.
Name of the font file to use instead of the default.
.IP 3\fIfont\fR 1i
Troff Font B.
Name of the font file to use instead of the default.
.IP 4\fIfont\fR 1i
Troff Font S.
Name of the font file to use instead of the default.
.IP W\fInum\fR 1i
Width.
Changes the page width (in characters) used by
.PN pr
and the text filters.
.IP Z\fInum\fR 1i
Length.
Changes the page length (in lines) used by
.PN pr
and the text filters.
.IP D\fIdata_type\fR 1i
Data type of the job.
.br
(PostScript (TM) printers only.)
.IP <\fIinput_tray\fR 1i
Selects the input tray that supplies paper for the print job.
.br
(PostScript (TM) printers only.)
.IP >\fIoutput_tray\fR 1i
Selects the output tray where the printed paper is deposited.
.br
(PostScript (TM) printers only.)
.IP O\fIorientation\fR 1i
Specifies the orientation of the printed output on the page.
.br
(PostScript (TM) printers only.)
.IP F\fIpage_size\fR 1i
Specifies the size of the pages being printed.
.br
(PostScript (TM) printers only.)
.IP S\fIsheet_size\fR 1i
Specifies the physical size of the sheets being printed.
.br
(PostScript (TM) printers only.)
.IP E\fImessage\fR 1i
Specifies what happens to messages generated when processing the print job.
.br
(PostScript (TM) printers only.)
.IP X\fInum\fR 1i
Specifies the number of times each page is printed.
.br
(PostScript (TM) printers only.)
.IP A\fInum\fR 1i
Specifies the first page to be printed for the job.
.br
(PostScript (TM) printers only.)
.IP B\fInum\fR 1i
Specifies the last page to be printed for the job.
.br
(PostScript (TM) printers only.)
.IP G\fInum\fR 1i
Specifies the number of pages to be printed on a single physical sheet.
.br
(PostScript (TM) printers only.)
.IP z\fIfilename\fR 1i
Layup definition file which alters the appearance of pages (margins, borders,
etc).
.br
(PostScript (TM) printers only.)
.IP K\fIsides\fR 1i
Specifies whether the job should be printed on both sides to the physical
sheet, and whether the pages should be rotated by 180 degrees.
.br
(PostScript (TM) printers only.)
.IP T\fItitle\fR
Title.
String to be used as the title for 
.PN pr .
.IP f\fIfilename\fR 1i
Formatted File.
Name of a file to print which is already formatted.
.IP p\fIfilename\fR 1i
Name of a file to print using 
.PN pr
as a filter.
.IP l\fIfilename\fR 1i
Like 
.PN f 
but passes control characters and does not make page breaks.
.IP t\fIfilename\fR 1i
Troff File.
The file contains 
.PN troff .
.IP n\fIfilename\fR 1i
Ditroff File.
The file contains
.PN ditroff
output (device independent
.PN troff ).
.IP d\fIfilename\fR 1i
DVI File.
The file contains TeX output (DVI format from Stanford).
.IP g\fIfilename\fR 1i
Graph File.
The file contains data produced by
.PN plot .
.IP v\fIfilename\fR 1i
The file contains a raster image.
.IP c\fIfilename\fR 1i
Cifplot File.
The file contains data produced by cifplot.
.IP r\fIfilename\fR 1i
The file contains text data with Fortran carriage control characters.
.IP x\fIfilename\fR 1i
Do not interpret any control characters in the file.
.IP U\fIfilename\fR 1i
Unlink.
Name of file to remove upon completion of printing.
.IP N\fIname\fR 1i
File name.
The name of the file which is being printed, or a blank
for the standard input (when 
.PN lpr
is invoked in a pipeline).
.SS PostScript (TM) Printers With Specialised Support
To use the features of the PostScript (TM) printers for which specialised
support is available, you must ensure that \fB:ps=LPS:\fR is
set in the appropriate entry in the
.PN /etc/printcap
file.
.PP
For PostScript (TM) printers, the line printer daemon assembles the PostScript
(TM)
from the users data files and PostScript (TM) device control modules.
The device control modules access device features and manipulate the
appropriate printer parameters.
Device control modules (the \fBDl\fR capability in
.PN /etc/printcap ),
are provided in an archive file, refer to
.PN ar(5) .
Device control modules access printer specific features of PostScript (TM)
and are therefore device dependent.
.PP
The data type of the spooled files is given by the \fBDa\fR capability in
the
.PN printcap
file.
The data type can be overridden by the \fBD\fR key character in the command
file.
.PP
The support for PostScript (TM) printers introduces a new method of
specifying the type of the data to be printed using the \fB\-D\fR option of
.PN lpr
or the \fBDa\fR capability in
.PN /etc/printcap .
The mechanism for invoking these translators needs to interact with the
existing mechanism for invoking filters for non-text files, so that the
existing mechanism can be used if required.
The mechanism has the following features:
.IP
The new translators are invoked via the shell program
.PN xlator_call ,
which is passed the data type as one of its parameters.
.IP
Any old style filter arguments (for example, \fB\-t\fR and \fB\-x\fR) take
precedence over \fB\-D\fR (even though
.PN lpr
will accept the combination).
This means that the \fBif\fR capability in
.PN /etc/printcap
must not be specified if data types are being used.
.SS Filter Capabilities
Two of the
.PN printcap
capabilities that affect the behaviour of
.PN lpd
require a more detailed explanation than that given on the
.PN printcap(5)
reference page.
.IP ct .3i
Connection type.
This entry in the
.PN printcap
file determines the type of connection.
The following table shows the valid choices for \fBct\fR, and the mandatory and
optional entries to go with each choice.
.sp 6p
.TS 
tab(@);
lfHB lfHB lfHB
lfR lfR lfR .
_
.sp 4p
ct=@Mandatory Entries@Optional Entries
.sp 6p
_
.sp 6p
.R
dev@lp@of
lat@lp, ts, op, os@of
remote@rp, rm@
network@of@
.sp 6p
_
.TE
.IP \& .3i
Remote means a printer that is connected to another system running a
compatible printing daemon.
Network means that the output filter does not use stdout (that is, no
\fBlp\fR) and is restarted for each job.
.IP uv .3i
ULTRIX version.
To enable the \fBct\fR capability to determine the type of connection,
and to ensure % escapes are expanded in all filter command strings, you
must have
.EX
:uv=psv1.0:
.EE
as part of the
.PN printcap
entry.
.SS Using Filter Capabilities
This section refers to the programs specified by
the following filter capabilities in the
.PN printcap
file: 
.PN cf , 
.PN df , 
.PN gf , 
.PN if , 
.PN nf , 
.PN of , 
.PN pp , 
.PN tf , 
.PN vf , 
.PN xf , 
.PN Lf , 
and
.PN Xf .
.PP
Filters may be specified as pipelines as well as simple commands.
The syntax accepts tab or space as word separators, and | to
set up a pipe connection.
You can specify arguments to the filters.
The individual commands may be specified as full path names or
as simple program names, in which case the path searched is:
.EX
/usr/local/lib/lpdfilters:/usr/ucb:/bin:/usr/bin:
                            /usr/lib:/usr/lib/lpdfilters
.EE
.SS Filter Argument Parameterisation
The arguments to the filter program are normally supplied automatically
by
.PN lpd
but you can assign your own arguments to filters.
When arguments are supplied automatically, they are put after the arguments
for the first command in a pipeline, or after the arguments of a simple
command.
.PP
If you want to assign your own arguments to filters, you must ensure that
\fB:uv=psv1.0:\fR is set in the appropriate entry in the
.PN printcap
file.
.PP
Arguments are supplied exactly as for previous
.PN lpd
releases
unless a special character (%) is found anywhere in the command.
If a % is found it tells
.PN lpd
that you have taken control
of passing arguments to the filter.
In this case, the default set of arguments
are no longer appended to the argument list.
The arguments supplied to the command are those specified in the command
string, but with
.PN lpd
replacing %x pairs with parameter strings.
.PP
To allow the special character, %, to be passed,
a pair of %%'s are replaced by a %.
It is an error to specify an unknown %x pair.
The %x pairs and the parameter strings that replace them are shown below.
.sp 6p
.TS
tab(@);
lw lw
lw lw.
.HB
_
.sp 6p
%x Pairs@Parameter String
.sp 6p
_
.sp 6p
.R
%%@%
%0@T{
null string (used to pass null argument or disable default arguments)
T}
%\&_@space (used to insert spaces in arguments)
%A@accounting file
%D@data type
%F@pagesize
%H@host where job was submitted
%I@indent
%j@job name
%J@T{
job id as shown by
.PN lpq
T}
%L@length
%O@orientation
%P@printer name
%T@title
%U@user's login name
%W@width
%X@pixel width
%Y@pixel length
.sp 6p
_
.TE
.PP
All of the above %x pairs are available to all input filters.
For a network printer (\fB:ct=network:\fR in the
.PN /etc/printcap
file) they are all available to the output filter \fBof\fR.
For dev and lat printers the per-job parameters (%H, %U, %J and
%j) are not available to the output filter.
This is because the output filter
is invoked per session so that per-job parameters are still unset.
.SS Filter Arguments Supplied By lpd
The arguments automatically assigned to each filter by
.PN lpd
are shown below.
For clarity the parameters for each argument are 
shown as the appropriate %x pair.
.sp 6p
.TS
tab(@);
lw lw
lw lw.
.HB
_
.sp 6p
Filter@Parameterised Form of Default Arguments
.sp 6p
_
.sp 6p
.R
cf@\-x%X \-y%Y \-n %U \-h %H %A
df@\-x%X \-y%Y \-n %U \-h %H %A
gf@\-x%X \-y%Y \-n %U \-h %H %A
if@\-w%W \-l%L \-n %U \-h %H %A
\&(when \c
.PN lpr \0\c
is invoked@
without the \fB\-l\fR option)@
if@\-c \-w%W \-l%L \-n %U \-h %H %A
\&(when \c
.PN lpr \0\c
is invoked@
with the \fB\-l\fR option)@
nf@\-w%W \-l%L \-n %U \-h %H %A
of@\-w%W \-l%L
pp@\-w%W \-l%L \-h %T
rf@\-w%W \-l%L \-n %U \-h %H %A
tf@\-x%X \-y%Y \-n %U \-h %H %A
vf@\-x%X \-y%Y \-n %U \-h %H %A
xf@(no arguments)
Lf@(no arguments)
Xf@%D %O %F %W %L %I
.sp 6p
_
.TE
.PP
The %A argument is only supplied if the \fBaf\fR capability
is present.
.SH Options
.IP \fB\-l\fR .3i
Log valid requests received from the network.
This can be useful for debugging purposes.
.IP \fB\-L\fIlogfile\fR .3i
Write error conditions to the file specified by the argument
\fIlogfile\fR.
If this option is not used, error conditions are written to the system
console.
.SH Files
.TP 25
.PN /etc/printcap
Printer description file
.TP
.PN /usr/spool/lpd
Spool directories
.TP
.PN /dev/lp*
Line printer devices
.TP
.PN /dev/printer
Socket for local requests
.TP
.PN /etc/hosts.lpd
Lists machine names allowed printer access
.TP
.PN /etc/hosts.equiv
Lists machine names allowed printer access as trusted machines
.SH See Also
lpq(1), lpr(1), lprm(1), printcap(5), lpc(8), pac(8), xlator_call(8)
.br
.I Guide to the BIND/Hesiod Service
.br
.I Guide to System Environment Setup