PRINTCAP(5)

NAME
printcap - printer capability data base

SYNOPSIS
printcap database

DESCRIPTION
The format of the LPRng printcap database was based on the termcap(5) data base file format. Entries in the printcap Each entry in the data base is used to define various options and values to control the printing and spooling of print jobs.

LPD.CONF, SYSTEM AND USER PRINTCAP FILES
Default configuration values are read from the LPRng configuration file /etc/lpd.conf, consult the lpd.conf(5) man page for details about them. The system printcap file /etc/printcap contains information common to all users and the LPRng printing system. Finally, the user printcap files is in ${HOME}/.printcap and contain user configurable information for printer information. The values in the user printcap file override values in the printcap file which override the default values in the /etc/lpd.conf file.

The user printcap file is used by client programs such as lpr , lprm , lpq , and lpq to allow the user to define either a special set of printers, provide additional configuration information, or to modify default settings in the /etc/printcap, or /etc/lpd.conf file.

CAPABILITIES
The printcap database files format is based on the termcap (5) database format, modified as follows. Leading whitespace on each line is discarded, and blank lines or lines which then start with a comment character (#) are discarded. A line which does not start with a colon (:) or bar (|) starts a printer entry definition. Lines ending with a backslash (\) are assumed to continue to the next line; this is for compatibility with other historical printcap file formats. Trailing blanks and tabs (whitespace) for an option value are deleted unless the last one is escaped with a backslash (``\''). If a colon character value is required then the \: escape sequence can be used, e.g.: dest=ftp\://address/file.

A printer definition starts with a primary printer name, followed by zero or more alternative printer names, followed by a set of keyword entries and values. For example:

#comment
# primary printer name
lp
#alternate names
 |lp2|lp3
 |Example of a printer
 :sd=/usr/spool/LPD/lp
 :rw:lp=/dev/lp:mx#100
include /etc/printcap/mainprintcap

The special printcap definition include will read the named file, which must have an absolute pathname, as the next set of printcap entries.

Keywords can be 1 to an indefinate number of characters long, and are case sensitive. Values for keywords can be strings (:st=string:), signed integer values using the C language notation, (:nu#12:max#-2:mask#0x1EF:), or flags (:flag: to set to 1, :flag@: to clear to 0). Integer values must be representable as 32 bit 2's complement numbers; care should be taken with extremely large numbers.

If the primary name of a printcap entry starts with a punctuation character, then the entry may be referenced using the tc capability, but is ignored otherwise. This allows common printcap information to be placed in a single entry.

The special printcap entry oh (i.e. - only this host) may be used to select a printcap entry for use by one or more hosts. The oh entry can be a list of one or more host names or glob type of patterns. These patterns are first applied to the host's fully qualified domain name, and then used to to a lookup of an IP address. If either the glob match or the host has a matching IP address then the printcap entry is selected for use. In addition, the server flag indicates that only the LPD server is to use this printcap entry. This allows client and server printcap information be to be segragated in a simple manner.

The following is a list of the keywords currently used by the LPRng software. Many of these keywords are used only by the LPD server, others are used by the client programs LPR, LPC, LPRM, PAC, as well as the server. In the Use column in the table below, an A stands for all programs, D stands for lpd, and R stands for the client programs such as LPR.

Some of these entries can only appear or have an effect if they are in the lpd.conf initialization file. See lpd.conf(5) for further details.

ENTRIES BY ALPHABETICAL ORDER

FL	Use	Type	Default	Description
Xf	D	str	NULL	output filter for format X (used by lpd).
				'filter' sets default filter
ab	D	bool	false	always print banner, ignore lpr -h option
achk	D	bool false
				If TRUE LPD and the :as specifies a remote host or
				filter or the :af specifies a remote host or filter
				then after writing the accounting information to the
				destination a resply will be read.  The value of the
				reply determines how the job is to be handled.
ae	D	str		accounting format for end of job or a program to run
				to record accounting information (see also af, la, ar
				and Accounting).
af	D	str	NULL
				accounting file, filter, or remote accounting server
				(see also la, ar, as, ae, achk). If format is |/path then
				the program will be started and accounting information
				will be written to the program STDIN.  If the format
				host%port, a tcp/ip connection will be made to port
				on host and the accounting information written to the
				remote host.  In both of these cases the write operation
				must succeed or an error will result.  If the format
				is neither of these cases then the value will be treated
				as a file and accounting information appended to the file
				if it exists.  The accounting file will not be created,
				it must exist for LPD to append data to it.
				The :as and :ae fields have the accounting information.
ah	D	bool	false	auto-hold - job held until explicitly released
all	A	str	NULL	a list of all printers; (see ALL PRINTERS)
allow_duplicate_flags	A	bool	false
				allow duplicate command line flags; last overwrites earlier
allow_getenv	A	bool	(compile time)
				allows LPRng software to use the LPD_CONF environment variable
				to specify the location of a configuration file.  This is
				for testing only.
allow_user_logging	A	bool	false
				if mail is requested using lpr -mhost%port,prot operations,
				and the allow_user_logging flag is true,  then job logging
				information will be sent to host%port,prot.
allow_user_setting  A  str NULL
				allow these users to impersonate other users with the
				lpr -U user@host, lpc -U user@host, etc., options
append_z	A	str
				append these options to the -Z options for the job
ar	D	bool	true	write remote transfer accounting (if af, and as/ae set)
architecture	A	str	(compile time)
				architecture the software was compiled for. (Obsolete.)
as	D	str		accounting format for start of job or a program to run
				to record accounting information (see also af, la, ar
				and Accounting).
auth	R	str	NULL
				client to server authentication type
be	D	str		banner printing program for end (overrides bp, hl)
bk	R	bool	false	Berkeley-compatible: be strictly RFC-compliant
				or more exactly, BSD LPR compatible when sending jobs.
bk_filter_options	D	str	(see source code)
				when bk flag set, options for non OF print filters
bk_of_filter_options	D	str	(see source code)
				when bk flag set, options for OF print filters
bkf	R	bool	false
				use bk_filter_options and bk_of_filter_options when
				invoking print filter.
bl	D	str		banner line - sent to banner printer program
				default: $-'C:$-'n Job: $-'J Date: $-'t
				expands to:  Class:User  Job: job Date: date
				This is to force compatibility with vintage print filters
				that require a non-standard banner string. Usually used with
				:sb: option.
bp	D	str		banner printing program (see hl)
				(default: configuration variable default_banner_printer)
bq_format	D	str	l	format of output from bounce queue filters
br	D	num	none	if lp is a tty, set the baud rate (see ty)
break_classname_priority_link	A	flag	false
				Do not set priority to first letter of class name
bs	D	str		banner printing program for start (overrides bp, hl)
cf	D	str	NULL	cifplot data filter
check_for_nonprintable	R	bool	false
				lpr checks f and p formats for printable files
check_for_protocol_violations	R	bool false
				check for RFC1179 protocol violations
chooser	D	str	load balance queue destination chooser program
chooser_interval	D	num	10
				load balance queue does checks for a
				destination queue available at this interval
chooser_routine	D	bool	false
				use the user provided chooser routine for this queue
class_in_status	A	bool	true
				show class name in lpq status rather than priority
cm	A	str	NULL	comment identifying printer (LPQ)
config_file	A	str	/etc/lpd.conf
				location of LPRng configuration information.  Compile
				time option only - see allow_getenv.
connect_grace	A	num	0
				time between jobs to allow printer recovery
connect_interval	A	num	10
				time between open or connection attempts
connect_timeout	A	num	10
				timeout value for connection or open
control_file_line_order	D	str	NULL
				Put the control file lines in a specific order
control_filter	D	str	NULL
				Filter for control file. Used when sending job to remote
				spool queue.
create_files	D	bool	false
				create log, debug, etc., files automatically
db	A	str	NULL	LPD debug options when serving this queue.
				See lf (log file) entry as well.
default_format	R	str	f
				default format for printing jobs
default_permission	D	str	A
				default permission for operation
default_printer	A	str	lp
				default printer for printing jobs
default_priority	R	str	A
				default priority for printing jobs
default_remote_host	A	str	localhost
				default remote host for printing operations
default_tmp_dir	A	str	/tmp
				default temporary directory
destinations	D	str	NULL
				names of printers that lpq/lprm should talk to
				find a job that has been processed by a router
				script (see README.routing)
df	D	str	NULL	tex data filter (DVI format)
done_jobs	D	num	1
				retain status for last N jobs
done_jobs_max_age	num	0
				remove status older than N seconds (0 - no removal)
exit_linger_timeout	A	num	10
				socket SO_LINGER timeout value
fd	D	bool	false	if true, no forwarded jobs accepted
ff	D	str	``\f''	string to send for a form feed (see INITIALIZATION)
filter	D	str	NULL
				default filter to use for printing file
filter_ld_path	D	str	(see source)
				the LD_LIBARY_PATH environment variable value for filters
filter_options	D	str	(see source code)
				when bk flag clear, options for non OF print filters
filter_path	D	str	(default '/bin:/usr/bin')
				the PATH environment variable value for filters
filter_poll_interval	D	num	30
				interval to poll OF filter
filter_stderr_to_status_file	D	bool	false
				set the filter STDERR to the status file and do
				no report errors in the queue status file.
fo	D	bool	false	print a form feed when device is opened
force_fqdn_hostname	A	bool	FALSE
				Force a fully qualified host name in control file
force_ipadddr_hostname	A	bool	FALSE
				Force the IP address of the host to be used for the
				hostname in control file
force_localhost	A	bool	TRUE
				Forces the clients programs (lpr, lpc, etc.)
				to send all print jobs and requests to the server running
				on the localhost entry for action.  This flag effectively
				forces BSD LPR behaviour.
force_lpq_status	D	str	NULL
				Specifies a list of LPQ formats and hosts which get status
				returned in this format.  For example
				force_lpq_status=s=pc*;l=mac* will cause hosts whose
				FQDN matches pc* to get short status and those which
				match mac* to get long format.
force_queuename	A	str	NULL
				When :qq: flag or use_queuename configuration is enabled,
				specifies the queuename to be used for control file Q
				information.
ff_separator	D	bool	false
				need form feeds to separate job files
fq	D	bool	false	print a form feed when device is closed
full_time	D	bool detailed time format specification in log messages
fx	A	str	NULL	valid output filter formats
				i.e. ``flp'' would allow f, l, and p
				default is to allow all formats
gf	D	str	NULL	graph data filter (plot (3X) format)
generate_banner	D	bool	false
				generate a banner when forwarding job
group	D	str	daemon	LPD server group id for execution
hl	D	bool	false	print banner after job instead of before
if	D	str	NULL	filter command, run on a per-file basis
ignore_requested_user_priority	D	bool	false
				Ignore the requested user priority when ordering jobs.
				Prevents students... um... users from queue jumping.
ipv6	A	bool	false	Use IPV6
keepalive	A	bool	true
				set socket SO_KEEPALIVE option
kerberos_keytab	D	str	/etc/lpd.keytab
				Kerberos lpd server keytab file
kerberos_life	D	str	NULL
				Kerberos lpd server key lifetime
kerberos_renew	D	str	NULL
				Kerberos lpd server key renewal time
kerberos_server_principle	D	str	NULL
				Kerberos remote lpd server principle
kerberos_service	D	str	lpr
				Kerberos service used in principle requests
la	D	bool	true	write local printer accounting (if af is set)
ld	D	str	NULL	leader string printed on printer open (see INITIALIZATION)
lf	D	str	``log''	error and debugging log file (LPD)
lk	D	bool	false	lock the lp device to force arbitration
lockfile	D	str	/var/spool/lpd/lpd
				lpd lock file (used only in lpd.conf).
                The lpd_port port value is appended
                to the lockfile value to provide a unique lockfile
                even when different versions of LPRng are running
                on the same system.
logger_destination	D	str	NULL
				destination for logging information.  Format is
				host%port
logger_max_size	D	num	1024
				logger file maximum size in K
logger_path	D	str	NULL
				logger file pathname
logger_timeout	D	num	0
				logger connection timeout.  0 is no timeout.
longnumber	D	bool	false
				use 6 digit job numbers
lp	D	str	NULL	device name or pipe to send output to
lpd_bounce	A	bool	FALSE
				Forces lpd to filter jobs and then forward them
				as a single file
				(See Bounce Queues)
lpd_force_poll	A	bool	FALSE
				Forces lpd to periodically poll lpd queues.
lpd_poll_time	A	num	600
				Check queues for work at this interval; start queues
				in groups of 'lpd_poll_servers_started' at intervals
				of 'lpd_poll_start_interval' seconds
lpd_poll_start_interval	A	num	10
				Start 'lpd_poll_servers_started' queue servers at this
				interval.
lpd_poll_servers_started	A	num	10
				Start 'lpd_poll_servers_started' queues at once
lpd_port	D	str	printer
                format is [ipaddr%]port.  If the ipaddr is present
                then the lpd listening socket is bound to the specified
                ip address and port only, otherwise it is bound to all
                interfaces. If the port value is not a number then the
				then the getservbyname() system call is used to get the
				port number.
lpd_printcap_path	D	str	(see source)
				printcap path for lpd, used instead of printcap path
				(configuration value only)
lpr_bounce	R	bool	true
				Forces lpr to filter jobs and then send them.
				(See Bounce Queues)
lpr_bsd	R	bool	false
				when set, LPR -m will not take argument, but will use
				$USER value for return mail address.
mail_from	D	str	NULL
				specifies the user part of email From: address
mail_operator_on_error	D	str	NULL
				send mail to this user when LPD encounters printing error.
max_connect_interval	A	num	60
				maximum time between connection attempts
max_log_file_size	D	num	0
				maximum log file size in K bytes (0 is unlimited)
				spool queue log file truncated to min_log_file_size
				when value is nonzero and limited exceeded.
max_servers_active	D	num	0
				maximum servers that LPD will allow to be active at one
				time.  0 selects the system default,  which is usually
				pretty small, perhaps 10. (configuration value only).
max_status_line	D	num	79	maximum number of characters on an LPQ status line
max_status_size	D	num	10	maximum size (Kbytes) of status file
mc	R	num	1	maximum copies allowed
min_log_file_size	D	num	0	minimum size (Kbytes) of log file
min_status_size	D	num	2	minimum size (Kbytes) of status file
minfree	D	str	0
				minimum space (in K) for spool directory
ml	R	num	32	minimum printable characters for printable check
ms_time_resolution	D	bool	false
				log time in milliseconds
mx	R	num	0	maximum job size in K, 0 = unlimited
nb	D	num	0	if non-zero, do a nonblocking open on lp device
nf	D	str	NULL	DITROFF data filter
network_connect_grace	A	num	0
				time between attempts to send jobs to spooler
				Useful when dealing with network printer using LPD
				interface to allow a bit of time between jobs.
nline_after_file	D	bool	false
				put the N (filename) after the data file information
				in the control file.  Use to handle systems that want
				it that way.
of	D	str	NULL	output filter, run once for all output
				(used for banner printing, form feeds between files)
of_filter_options	D	str	(see source code)
				when bk flag clear, options for OF print filters
oh	A	str	NULL	Specific printcap entry for host;
				(printcap entry ignored unless IP address of host and
				entry value match.  Entry is used first to do glob
				style match against the host's fully qualified domain name,
				and then interpreted as a general IP address)
order_routine	D	bool	false
				use a user provided routine to generate queue order
				information.
originate_port	A	str	512 1023
				when originating a connection, use ports in this range.
pass_env	A	str	PGPPASS,PGPPATH
				if not the LPD server, sanitize and put these variables
				in a filter environment variable list.
perms_path	A	str	/etc/lpd.perms
				location of perms file (used in lpd.conf)
pl	D	num	66	page length (in lines)
pr	D	str	``/bin/pr''	pr program for p format
prefix_o_to_z	D	bool	false
				prefix the control file O line to the control file
				Z line.
prefix_z	D	str	NULL
				prefix the specified options to the control file
				Z line.
prefix_z_to_o	D	bool	false
				prefix the control file Z line to the control file
				O line.
printcap_path	A	str	/etc/printcap
				location of printcap file (only in lpd.conf)
ps	A	str	''status''	printer status file name
pw	D	num	132	page width (in characters)
px	D	num	0	page width in pixels (horizontal)
py	D	num	0	page length in pixels (vertical)
qq	A	bool	false	LPR - puts in the queue name (Q entry)
				in the job control file when spooled or transferred.
				LPD - when receiving or transferring a job,
				if the queue name (Q entry) in the job control
				file is not present,  puts in the queue name.
queue_control_file	D	str	control.%P
				name of the queue control file
queue_lock_file	D	str	%P
				name of the queue lock file
queue_status_file	D	str	status.%P
				name of the queue status file
queue_unspooler_file	D	str	unspooler.%P
				name of the queue unspooler status file
remote_support	A	str	NULL
				if non-null, specifies allowed operations to remote queue.
				R=lpr, M=lprm, Q=lpq, V = lpq -v, C=lpc.  For example,
				remote_support=RM would only allow LPR and LPRM operations.
remove_z	D	str	null
				remove these options from the control file Z line
report_server_as	A	str	NULL
				use the str value as the name of the server when reporting
				LPQ or LPC status.
require_explicit_q	Require a queue to be specified, do not use default
				queue from printcap.
retry_econnrefused	A	bool	true
				if set, retry a connection to a remote system when an
				ECONNREFUSED error is returned.
retry_nolink	D	bool	true
				if LPD is sending a job or opening a device for
				printing and the value is true, then the connection or
				device open is repeated indefinately.
return_short_status	D	str	NULL
				Some legacy (non-LPRng) LPQ programs expect 'short' status
				to be returned.  This option allows you to specify which hosts
				will get it.  The value is a list of hosts and/or IPaddresses
				and masks to which the LPD server will provide short status.
				For example:  return_short_status=192.8.0.0/16 will make LPD
				return short status to all requests from hosts in subnet
				192.8.0.0.  (See short_status_length)
reuse_addr	A	bool	false
				if set, use SO_REUSEADDR on outgoing connection ports.
				This reduces the problems with exhausting port numbers.
				(usually only in lpd.conf)
reverse_lpq_status	D	str	NULL
				When a lpq status request arrives from one of the specified
				hosts or IP addresses,  then the LPQ status format is inverted.
				For example, if  reverse_lpq_status=host*,127.0.0.0/8,
				then when a LONG status request arrives from host1 or from
				ip address 127.0.0.1,  the SHORT status will be returned.
reverse_priority_order	D	bool	false
				Make highest priority A, lowest Z
rf	D	str	NULL	filter for printing FORTRAN style text files
rg	A	str	NULL	(restrict to group members)
				Restrict use of queue to users which are members of
				specified groups.
rm	A	str	NULL	remote-queue machine (hostname) (with rp)
router	D	str	NULL	script that dynamically re-routes a job
				(see README.routing)
rp	A	str	NULL	remote-queue printer name (with rm)
rw	D	bool	false	open the printer for reading and writing
safe_chars	D	str	NULL
				additional safe characters for control file contents
save_on_error	D	bool	false
				Save job when an error occurs to allow post-mortem
				diagnostics or reprinting.  This should only be set on
				print queues.  It is also a diagnostic aid.
save_when_done	D	bool	false
				Save job when done (printed, transferred) to allow
				retry at a later time.  This should only be set on
				print queues.  It is also a diagnostic aid.
sb	D	bool	false	short banner (one line only)
sd	A	str	NULL	spool directory (only ONE printer per directory!)
send_block_format	A	bool	false
				Use the LPRng extended 'block job' job transmission
				method to send a job to a remote site.
send_data_first	A	bool	false	send data files then control files
				when sending a job to a remote host.
send_failure_action	D	str	"remove"
				Action on print or transmission failure after send_try
				attempts; use the following codes:
				'success' (JSUCC)  - treat as successful
				'abort'   (JABORT) - abort printer
				'retry'   (JRETRY) - retry job
				'remove'  (JREMOVE)- remove job
				'hold'    (JHOLD)  - hold job
				If the value is "|/filter", the filter will be run and
				the number of attempts can be read from standard input.
				The filter should exit with one of the error codes listed
				above to cause the appropriate action.
send_job_rw_timeout	A	num	6000
				timeout on read/write operations when sending job to
				printer or remote host (0 value is no timeout)
send_query_rw_timeout	A	num	6000
				timeout on read/write operations when performin a status
				operation (0 value is no timeout)
send_try	A	num	3
				number of times to try sending
				or printing a job. 0 is infinite.
sendmail	D	str	/usr/sbin/sendmail -oi -t
				sendmail command to send mail to user.  Flags must be set
				so that address and other information is taken from
				standard input.
server	A	bool	false	printcap entry for server only
server_auth_command	A	str	NULL
				authentication command for server program
server_tmp_dir	D	str	/tmp
				temporary directory for server to create files when there
				is no spool directory.
server_user	D	str	daemon	server user name used in authentication operations
sf	D	bool	true	suppress form feed separators between job files
sh	D	bool	false	suppress headers and/or banner page
shell	D	str	/bin/sh
				SHELL enviornment variable value for filters
short_status_length	D	num	1
				If the return_short_status value is used and has a match against
				a requesting address, this amount of status is set by the
				short_status_length option.  For most legacy systems a 1 is
				suitable (1 line of status).
socket_linger	A	num	10
				if nonzero, forces a SO_LINGER operation to be done
				on all TCP/IP connections.  This usually corrects a problem
				with missing last data transmissions to remote hosts.
spool_dir_perms	D	num	042700	permissions for spool directory
spool_file_perms	D	num	0600	permissions for spool file
ss	D	str	NULL	name of queue that server serves (with sv)
ssl_XXX	D	str	NULL
				SSL authentication and encryption options.
				See lprng_certs(1) for details.
ssl_ca_file	str	A	/etc/lpd/ssl.ca/ca.crt
				SSL signing certificate file
ssl_ca_path	str	A	NULL
				SSL signing certificate directory. Default is
				directory containing ssl_ca_file.
ssl_server_cert	str	A	/etc/lpd/ssl.server/server.crt
				SSL server certificate
ssl_server_password	str	A	@SSL_SERVER_PASSWORD@
				SSL server certificate password
stalled_time	D	num	120
				Time after which to report an active job as stalled
stop_on_abort	D	bool	true
				Stop processing queue when print filter aborts.
stty	D	str	NULL	stty settings for serial connected printer
suspend_of_filter	D	bool	true
				suspend OF filter and restart.  If false, close filter
				and start new one for each activity.
sv	D	str	NULL	names of servers for queue (with ss)
syslog_device	D	str	/dev/console
					name of syslog device to use if no syslog facility
tc	A	str	NULL	reference to a printcap entry to include as part of
				the current entry.
tf	D	str	NULL	troff data filter (C/A/T phototypesetter)
tr	D	str	NULL	trailer string to print when queue empties
translate_format	D	str	NULL
				translate job format (similar to tr(1) utility)
				on outgoing jobs.
				Example: translate_format=pfml
				p format changed to f, m format to l
translate_incoming_format	D	str	NULL
				translate job format (similar to tr(1) utility)
				on incoming jobs.  See translate_format.
use_date	A	bool	true add date line ('D') to control file
use_identifier	R	bool	true
				add job identifier lines ('A') in the control file
use_info_cache	D	bool	true	cache printcap information
use_shorthost	R	bool	false
				use only the hostname for job control
				and data file names.  Host information in job file
				will still be fully qualified domain name.
user	D	str	daemon	LPD effective user (EUID) for SUID operations
wait_for_eof	D	bool	true
				wait for EOF on input when readable IO device,
				do not close immediately at job end.
vf	D	str	NULL	(Versatek) raster image filter

ENTRIES BY FUNCTION

See the alphabetical listing for detailed information.

Filters and Page Formats
Xf	D	str	NULL	output filter for format X (used by lpd)
				'filter' sets default filter
cf	D	str	NULL	cifplot data filter
control_filter	D	str	NULL
				Filter for control file. Used when sending job to remote
				spool queue.
df	D	str	NULL	tex data filter (DVI format)
direct_read	D	bool	false
				if true, filters are given direct access to file.
				This means no progress indication possible.
fx	A	str	NULL	valid output filter formats
				i.e. ``flp'' would allow f, l, and p
				default is to allow all formats
gf	D	str	NULL	graph data filter (plot (3X) format)
if	D	str	NULL	filter command, run on a per-file basis
lpd_bounce	R	bool	false
				Forces lpd to filter jobs and then forward them.
				(See Bounce Queues)
lpr_bounce	R	bool	false
				Forces lpr to filter jobs and then send them.
				(See Bounce Queues)
nf	D	str	NULL	DITROFF data filter
of	D	str	NULL	output filter, run once for all output
pl	D	num	66	page length (in lines)
pr	D	str	``/bin/pr''	pr program for p format
pw	D	num	132	page width (in characters)
px	D	num	0	page width in pixels (horizontal)
py	D	num	0	page length in pixels (vertical)
rf	D	str	NULL	filter for printing FORTRAN style text files
translate_format	D	str	NULL
				translate job format (similar to tr(1) utility)
				only valid when transferring to remote spool queue.
				Example: translate_format=pfml
				p format changed to f, m format to l
tf	D	str	NULL	troff data filter (C/A/T phototypesetter)
vf	D	str	NULL	(Versatek) raster image filter
Banners
ab	D	bool	false	always print banner, ignore lpr -h option
be	D	str		banner printing program for end (overrides bp, hl)
bp	D	str		banner printing program (use hl to print banner at end)
bs	D	str		banner printing program for start (overrides bp, hl)
hl	D	bool	false	print banner after job instead of before
sb	D	bool	false	short banner (one line only)
sh	D	bool	false	suppress headers and/or banner page, overrides ab
Accounting
ae	D	str		accounting format for end of job or a program to run
                to record accounting information (see also af, la, ar
				and Accounting).
af	D	str	NULL	name of accounting file (see also la, ar)
ar	D	bool	true	write remote transfer accounting (if af, and as/ae set)
as	D	str		accounting format for start of job or a program to run
                to record accounting information (see also af, la, ar
				and Accounting).
la	D	bool	true	write local printer accounting (if af is set)
Queue control
ah	D	bool	false	auto-hold - job held until explicitly released
bk	R	bool	false	backwards-compatible: be strictly RFC-compliant
bkf	R	bool	false	backwards-compatible filter: use Berkeley filter options
bqfilter	D	bool	false	if a bounce queue (sends jobs to remote site)
				then when bqfilter true and a format filter is specified,
				sends data files through format filter before transfer.
				See also 'qq'.
cd	D	str	NULL	control information directory for LPD server
cm	A	str	NULL	comment identifying printer (LPQ)
fd	D	bool	false	if true, no forwarded jobs accepted
lf	D	str	``log''	error and debugging log file (LPD)
longnumber	D	bool	false
				use 6 digit job numbers
mc	R	num	1	maximum copies allowed
ml	R	num	32	minimum printable characters for printable check
minfree	D	str	0	minimum space (Kb) to be left in spool filesystem
				You can also use nnnM for nnn megabytes.
mx	R	num	0	maximum job size (1Kb blocks, 0 = unlimited)
ps	A	str	''status''	printer status file name
nw	A	bool	false	spool dir is on an NFS file system
				(take precautions when reading/writing files)
qq	A	bool	false	place queue information in control file. See
				alphabetical for details.
rm	A	str	NULL	remote-queue machine (hostname) (with rp)
rp	A	str	NULL	remote-queue printer name (with rm)
sd	A	str	NULL	spool directory (only ONE printer per directory!)
ss	D	str	NULL	name of queue that server serves (with sv)
sv	D	str	NULL	names of servers for queue (with ss)
sc	R	bool	false	suppress multiple copies
use_auth	A	str	NULL authentication to use
use_date	A	bool	true add date line ('D') to control file
use_identifier	R	bool	true
				add job identifier lines ('A') in the control file
use_shorthost	R	bool	false	use only the hostname for job control
				and data file names.  Host information in job file
				will still be fully qualified domain name.
Connection and Interface to Printer
db	A	num	0	debug level when using this printer
connect_interval	A	num	10
				time between open or connection attempts
connect_timeout	A	num	10
				timeout value for connection or open
				(0 is infinite number)
ff	D	str	``\f''	string to send for a form feed (see INITIALIZATION)
fo	D	bool	false	print a form feed when device is opened
fq	D	bool	false	print a form feed when device is closed
ld	D	str	NULL	leader string printed on printer open (see INITIALIZATION)
lp	D	str	NULL	device name or pipe to send output to
lk	D	bool	false	lock the lp device to force arbitration
max_connect_interval	A	num	60
				maximum time between connection attempts
nb	D	num	0	if non-zero, do a nonblocking open on lp device
retry_econnrefused	A	bool	true
				if set, retry a connection to a remote system when an
				ECONNREFUSED error is returned.
retry_nolink	D	bool	true
				if LPD is sending a job or opening a device for
				printing and the value is true, then the connection or
				device open is repeated indefinately.
rs	D	num	300	number of seconds between spool queue status scans
rt	D	num	3	number of times to try printing (0=infinite).
rw	D	bool	false	open the printer for reading and writing
save_on_error	D	bool	false
				See above.
save_when_done	D	bool	false
				See above.
send_failure_action	D	str	remove
				See above.
send_try		alias for rt
sf	D	bool	true	suppress form feed separators between job files
socket_linger	A	num	10
				if nonzero, forces a SO_LINGER operation to be done
				on all TCP/IP connections.  This usually corrects a problem
				with missing last data transmissions to remote hosts.
tr	D	str	NULL	trailer string to print when queue empties
Serial Line Setup
br	D	num	none	if lp is a tty, set the baud rate (see ty)
stty	D	str	NULL	stty commands to set output line characteristics
				alias is sy, ms
xs	D	num	0	like `xc' but set bits (see STTY)
Miscellaneous
all	A	str	NULL	a list of all printers; (see ALL PRINTERS)
destinations	D	str	NULL
				names of printers that lpq/lprm should talk to find
				a job that has been processed by a router script
				(see README.routing)
forward_auth	D	str	NULL
				server to server authentication type, e.g. pgp, kerberos
force_localhost	A	bool	TRUE
				Forces the clients programs (lpr, lpc, etc.)
				to send all print jobs and requests to the server running
				on the localhost entry for action.  This flag effectively
				forces BSD LPR behaviour.
force_queuename	A	str	NULL
				See above.
logger_destination	D	str	NULL
				destination for logging information.  Format is
				host[%port][,(TCP|UDP)]
oh	D	str	NULL	Specific printcap entry for host. See above.
remote_support	A	str	RMQC
				if non-null, specifies allowed operations to remote queue.
				R=lpr, M=lprm, Q=lpq, C=lpc
router	D	str	NULL	script that dynamically re-routes a job
				(see README.routing)
server	A	bool	false	printcap entry for server only
server_auth_command	D	str	NULL
				authentication command for server to use.
tc	A	str	NULL	reference to a printcap entry to include as part of
				the current entry.
use_auth	D	str	NULL
				client to server authentication type, e.g. pgp, kerberos
user_auth_command	R	str	NULL
				authentication command for user (client program)

FILTERS

By convention, all output filter names have the form Xf, where X is the lower case letter corresponding to the lpr formatting option. The filter option can specify a default filter for job files.

The of filter is started for each job and is used to print the banner page and any FF separators between individual files of the job. It is sent a special stop sequence by the lpd server, and must suspend operations until sent a SIGCONT signal. A file or job filter is run separately for each file; at the end of the job the of filter is restarted and used to print the trailing banner (if any) and FF separators.

Filters are invoked with a standard set of options defined by the bk_filter_options (backwards compatible), bk_of_filter_options (backwards compatible OF filter), and filter_options configuration variables. See the lpd(8) manual page for details. If the first characters of the filter specification are -$, i.e.- Xf=-$ filter, then the command line options are not added. Currently, the options are:
bk_filter_options $P $w $l $x $y $F $c $L $i $J $C $0n $0h $-a
bk_of_filter_options $w $l $x $y
filter_options $C $F $H $J $L $P $Q $R $Z $a $c $d \
    $e $f $h $i $j $k $l $n $s $w $x $y $-a

SPOOL QUEUES

Printcap entries which have a spool directory value (sd) are called spool queues. Jobs sent to a printer with a spool queue are place in the spool directory. When checking the spool queue for jobs, the server will check to see if there is a printcap file in the directory with the name printcap.host. If there is, the additional printcap information is processed and used by the server.

If the spool directory is NFS exported, then remote hosts can manipulate the spool entries directly; this can have catastrophic effects, especially in systems where the NFS implementation has defects. The printcap information is particularly vulnerable to exploitation, as well as symbolic links, jobs which cannot be removed, etc.

LOCAL PRINTERS

Local printers have an lp entry, which is the device that output should be sent to, usually a serial port tty. PLP supplements this by using the lp field to indicate a remote printer, or by allowing communication with the printer using a separate program, known as an lp-pipe, instead of a serial line. If the printcap lp entry contains a string of the form printer@host, jobs are forwarded to the specified remote printer on the host. If the printcap lp entry contains a string of the form | command args , the command command is run, with the arguments args . This can be used to communicate with printers connected to network terminal servers, some TCP/IP-capable printers, and just about anything you can hack up a communication program for. Read the PLP Manual for more details.

STTY OPTIONS

The stty printcap parameter recognises a set of stty(1) options that can be used to set serial line characteristics for the printer. However, due to the differences between implementations of UNIX, there are several sets of ty options supported. Invoke lpd(8) with the ``-v'' command-line option to see which set your installation is using.

Systems using the sgtty tty manipulation interface may use the following stty(1) options:

bs0	bs1	[-]cbreak	cooked	cr0
cr1	cr2	cr3	[-]decctlq	[-]echo
[-]even	ff0	ff1	[-]lcase	[-]litout
nl0	nl1	nl2	nl3	[-]nl
[-]noflsh	new	[-]nohang	old	[-]odd
[-]raw	start	stop	tab0	tab1
tab2	[-]tabs	[-]tandem	tek	ti700
[-]tilde	tn300	tty33	tty37	vt05
[-]evenp	[-]oddp	[-]pass8

Systems using termio may use the following options:

[-]ignbrk	[-]brkint	[-]ignpar	[-]parmrk	[-]inpck
[-]istrip	[-]inlcr	[-]igncr	[-]icrnl	[-]iuclc
[-]ixon	[-]ixany	[-]ixoff	[-]decctlq	[-]tandem
[-]imaxbel	[-]opost	[-]olcuc	[-]onlcr	[-]ocrnl
[-]onocr	[-]onlret	[-]ofill	[-]ofdel	[-]cstopb
[-]cread	[-]parenb	[-]parodd	[-]hupcl	[-]clocal
[-]loblk	[-]parity	[-]evenp	[-]oddp	[-]stopb
[-]hup	[-]crtscts	[-]isig	[-]noisig	[-]icanon
[-]cbreak	[-]xcase	[-]echo	[-]echoe	[-]echok
[-]crterase	[-]lfkc	[-]echonl	[-]noflsh	[-]tostop
[-]echoctl	[-]ctlecho	[-]echoprt	[-]prterase	[-]echoke
[-]crtkill	[-]lcase	[-]nl	[-]litout	[-]pass8
[-]raw	[-]sane	[-]cooked	[-]nopost	fill
nl0	nl1	cr0	cr1	cr2
cr3	tab0	tab1	tab2	tab3
bs0	bs1	vt0	vt1	ff0
ff1	cs5	cs6	cs7	cs8
nul-fill	del-fill	-tabs

And systems using termios may use the following options:

[-]ignbrk	[-]brkint	[-]ignpar	[-]parmrk	[-]inpck
[-]istrip	[-]inlcr	[-]igncr	[-]icrnl	[-]iuclc
[-]ixon	[-]ixany	[-]ixoff	[-]imaxbel	[-]pass8
[-]opost	[-]olcuc	[-]onlcr	[-]ocrnl	[-]onocr
[-]onlret	[-]ofill	[-]ofdel	[-]tabs	nl0
nl1	cr0	cr1	cr2	cr3
tab0	tab1	tab2	tab3	bs0
bs1	vt0	vt1	ff0	ff1
cs5	cs6	cs7	cs8	[-]cstopb
[-]cread	[-]parenb	[-]parodd	[-]hupcl	[-]clocal
[-]crtscts	[-]evenp	[-]parity	[-]oddp	[-]pass8
[-]isig	[-]icanon	[-]xcase	[-]echo	[-]echoe
[-]echok	[-]echonl	[-]noflsh	[-]tostop	[-]iexten
[-]echoctl	[-]ctlecho	[-]echoprt	[-]prterase	[-]echoke
[-]crtkill	[-]flusho	[-]pendin

The fc , fs , xc , and xs printcap entries are obsolete, and if present with non-zero values will abort print job processing.

INITIALIZATION

Many printers require an initialization string to be sent to them in order to configure their operation. The leader (ld) and trailer (tr) strings are sent at the start and end of job processing. These strings are interpreted using the C language conventions for character representation: \nnn is replaced with a character with the value nnn, \n with a new line, \r with a carriage return, and so forth.

ALL PRINTERS

The LPRng software has the capability to use a remote database for obtaining printcap and other information. One of the difficulties arises when a list of all printers available is needed. By convention, the special printer name all is reserved for this information; the all field is a list of printers separated by spaces or punctuation. For example:

#all printers
all:all=lp1,lp2,lp3,lp4

ACCOUNTING

Accounting in the LPRng package has evolved over time to accommodate new requirements. The general approach is to use either a simple log to file method in which the accounting information is written to a log file or a more complex log to program method in which the accounting information is written to a program. The information and method and actions taken are specified by the following entries:
:as  - start of job accounting
:ae  - end of job accounting
:af  - default job accounting
:achk - used accounting for authorization.

The value of the :as and :ae options are either a string which is used as the accounting information or a program which is executed to log or save the accounting information. If a program is executed then the value of the :af entry is ignored and the program is run to record the job accounting information. For example:
# string for information logging
:as=jobend $H $n $P $k $b $t
:ae=jobstart $H $n $P $k $b $t
:as=|/usr/local/libexec/logjobstart $H $n $P $k $b $t
:ae=|/usr/local/libexec/logjobend $H $n $P $k $b $t

If the :as or :ae value is a string then the :af information is used to record the accounting information:
af=|/path    - run program, :as or :ae written to
               program STDIN
af=host%port - tcp/ip connection to port on host,
               :as or :ae written to connection
af=path      - treat path as a file pathname,
               if file exists append :as or :ae
               to file.

If the :achk flag is set then this is modified as follows.
If the :as entry specifies a program or :af entry specifies a
program or remote host (i.e. - logging using program) then
after accounting information has been written to the
program or connection a response will be read from the program
STDOUT or the connection.
This reponse is expected to be an ASCII string.
If the line is blank or starts with ACCEPT then the job will be printed,
HOLD will hold the job,  REMOVE will remove the job,
and ABORT or a non-recognizable response will cause printing to be aborted.

If the output is written to a program then the exit status
of the program can be used as well.
If the program exits with nonzero status then the
exit code controls the disposition:
JHOLD, JREMOVE, and JABORT will hold, remove,
or abort the job respectively.
If the exit status is 0, then
the filter's STDOUT will be read and processed as described above.

BOUNCE QUEUES AND PRINT FORMATS

If the lp option value has the format :lp=pr@host or job forwarding is specified by :rp=pr:rm=host then the normal operation is simple to store and forward the print jobs. If filters are specified then the job files are first filtered and then the output of the filters is sent to the destination. For historical reasons, a spool queue that does filtering and forwarding is called a bounce queue. The bounce_queue_format (default 'f') specifies the output for the filtered files. If this is not desireable the translate_format option can be used to specify a format. The option has the form SdSdSdN, where S is the original format and d is the final format. If none of the formats match and there is an odd number of formats then the last one is used. For example, pfmlf would convert formats p to f, m to l, and v to f.

The :lpd_bounce flag concatenate the output of the filters and the result will be sent as a single job file to the destination. This facility is useful when handling legacy print spooler applications that do not understand the RFC1179 copy, etc., options. The first letter of the bounce_queue_format (default 'f') is used as the output file format.

The lpr_bounce printcap flag can be used to cause LPR to do bounce queue filtering in exactly the same manner as the server. This should be used with caution as missing filters on the client system can cause unexpected behaviour.

KERBEROS, PGP, AND OTHER AUTHENTICATION METHODS

LPRng supports built in kerberos authentication. To enable this, the LPD protocol has been extended to provide a way to transfer authenticated and/or encrypted jobs and commands. The details are covered in the LPRng HOWTO documentation.

Also, SSL can be used. See lprng_certs(1) for details.

FILES

The files used by LPRng are set by values in the printer configuration file. The following are a commonly used set of default values.
/etc/lpd.conf	LPRng configuration file
${HOME}/.printcap	user printer description file
/etc/printcap	printer description file
/etc/lpd.perms	permissions
/var/run/lpd	lock file for queue control
/var/spool/lpd		spool directories
/var/spool/lpd/QUEUE/control	queue control
/var/spool/lpd/QUEUE/log	trace or debug log file
/var/spool/lpd/QUEUE/acct	accounting file
/var/spool/lpd/QUEUE/status	status file

SEE ALSO
lpd.conf(5), lpc(8), lpd(8), checkpc(8), lpr(1), lpq(1), lprm(1), lpd.perms(5), pr(1), lprng_certs(1), lprng_index_certs(1).

DIAGNOSTICS
Most of the diagnostics are self explanatory.
If you are puzzled over the exact cause of failure,
set the debugging level on (-D5) and run again.
The debugging information will
help you to pinpoint the exact cause of failure.

HISTORY
LPRng is a enhanced printer spooler system with functionality similar to the Berkeley LPR software. The LPRng mailing list is lprng@lprng.com; subscribe by sending mail to lprng-request@lprng.com with the word subscribe in the body. The software is available from ftp://ftp.lprng.com/pub/LPRng.

AUTHOR
Patrick Powell <papowell@lprng.com>.