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The Printing Cookbook
Updated 5 Sept 2003
Patrick A Powell
<papowell@lprng.com>
AStArt Technologies
6741 Convoy Court,
San Diego, CA 92111
Phone 858-874-6543
Fax 858-751-2435
Copyright © 2001-2003 Patrick Powell
- Table of Contents
- Preface
- 1. Introduction - The Basics and Variations
- 2. Simple Spooling
- 3. Printers
-
- 3.1. Interface
- 3.2. Parallel Port
- 3.3. Network Ports
- 3.4. Sending To SMB (Samba, Microsoft) Printer, Novell, Appletalk
- 3.5. Serial Port
- 4. Printer Job Formats
-
- 4.1. PostScript
- 4.2. PCL
- 4.3. Printer Job Language (PJL) and PostScript, PCL
- 4.4. Text Files
- 4.5. Magical Mystery Proprietary Format
- 4.6. Printing Test Pages
- 5. Filters
- 6. Banner Pages and Accounting
- 7. Printer Pools and Load Sharing
- 8. Wildcards, Bounce Queues, and Forwarding
- 9. Form Support and Hold Queues
-
- 9.1. Hold Queues
- 10. Interfacing to Vintage, Legacy, and SunOS Print Spoolers
- 11. Managing Enterprise Level Printing Systems
- 12. LPRngTool
- A. LPRng
-
- A.1. Documentation
- A.2. Installation
- A.3. License
- A.4. Commercial Support
- A.5. Web Site, FTP Site, and Mirrors
- A.6. Mailing List
- A.7. PGP Public Key
- B. References and Standards
-
- B.1. RFCs
- B.2. PostScript
- B.3. HP PCL 5
- B.4. HP PJL
- B.5. PDF
- C. RFC 1179 - Line Printer Daemon Protocol
-
- C.1. Ports and Connections
- C.2. Protocol Requests and Replies
- C.3. Job Transfer
- C.4. Data File Transfer
- C.5. Control File Contents
- C.6. lpq Requests
- C.7. lprm Requests
- C.8. LPC Requests
- C.9. Block Job Transfer
- C.10. Authenticated Transfer
- List of Tables
- 3-1. Network Print Server Configuration Information
- C-1. RFC1179 Commands
- C-2. Control File Lines and Purpose
- C-3. LPC Commands
- List of Figures
- 1. lpq status
- 1-1. Print Spooler Architecture
- 1-2. Configuration Files
- 1-3. Printcap
- 1-4. lpd.conf Defaults File
- 1-5. lpd.perm Permissions File
- 1-6. Clients and Configuration Files
- 1-7. ${HOME}/.printcap Information
- 1-8. Using checkpc
- 1-9. Using checkpc -f
- 2-1. Basic Printcap Entry
- 2-2. Run checkpc
- 2-3. Check for Running Server
- 2-4. Run lpq
- 2-5. Run lpc
- 2-6. Run lpr
- 2-7. Run lprm
- 2-8. Enable Printing
- 2-9. Using lpr -V
- 2-10. The lpr Options
- 2-11. Debug Options
- 2-12. The lpr -D1 Output
- 2-13. Using lpr -Dnetwork
- 2-14. Debugging lpq
- 2-15. Basic lpq Information
- 2-16. Using the lpq -l Option
- 2-17. Using the lpq -L Option
- 2-18. Job Completion
- 2-19. Summary Status Displays
- 2-20. lpd Options
- 2-21. Using lpd Debug Options
- 2-22. Debugging Spool Queue
- 2-23. Setting Queue Debug Options
- 2-24. log File
- 3-1. Printer Types
- 3-2. Interface Types
- 3-3. Parallel Port
- 3-4. Parallel Port Printcap
- 3-5. Loading Linux Parallel Port Driver
- 3-6. Parallel Port Problems
- 3-7. Network Ports
- 3-8. Network Port Printcap
- 3-9. Benefits of Network Port Printcap
- 3-10. Network Print Server
- 3-11. Using Program To Send To Printer
- 3-12. Protocols, Packages, and Transfer Programs
- 3-13. Printcap For Transfer Programs
- 3-14. Samba smbclient Wrapper
- 3-15. $PRINTCAP_ENTRY
- 3-16. Novell and Appletalk Wrappers
- 3-17. Serial Port
- 3-18. Serial Port Printcap
- 4-1. Page Description Lanaguages
- 4-2. How To Identify Print Formats
- 4-3. Using the file Application
- 4-4. One PostScript Page
- 4-5. Generate One Page
- 4-6. PostScript Document Structuring Conventions
- 4-7. Tools for PostScript Document Manipulation
- 4-8. Selection of Pages + 4up Printing
- 4-9. PostScript Output
- 4-10. End Of PostScript Job: ^D (CTRL-D)
- 4-11. One PCL Page
- 4-12. Generate One Page
- 4-13. PJL Example
- 4-14. Text Files and The Jaggies
- 4-15. Fixing The Jaggies
- 4-16. Magical Mystery Formats
- 4-17. GhostScript To The Rescue
- 4-18. GhostScript Devices
- 4-19. GhostScript Support
- 4-20. Printing Test Pages To Parallel Port
- 4-21. Using Netcat (nc)
- 5-1. Filters
- 5-2. Filter Specification in Printcap Entry
- 5-3. Specifying Job Datafile Format
- 5-4. Filter Execution Environment
- 5-5. Command Line Options
- 5-6. Filter Exit Codes
- 5-7. Solid As A Rock Filter Operation
- 5-8. Solid As A Used Paper Coffee Filter Operation
- 5-9. Filter Template in perl
- 5-10. How To Determine The Type of Job File
- 5-11. Printcap for Filter
- 5-12. Using Filter With $debug=1
- 5-13. Using Filter With $debug=0
- 5-14. ifhp
- 5-15. ifhp.conf Configuration Information
- 5-16. Default Printer Magic Cookies
- 5-17. PostScript Only Printer
- 5-18. Using the ifhp Filter
- 5-19. Example of ifhp Operation
- 5-20. Using -Z to Pass Options to ifhp
- 5-21. Testing ifhp Operations
- 5-22. Phaser/Appsocket Support
- 6-1. Changing JetDirect Configuration
- 6-2. Printcap Option :sh and lpr -h (No Header) Option
- 6-3. Removing Banner Lines
- 6-4. Forcing Banner Pages
- 6-5. Generating Banner Page
- 6-6. Basic Accounting Information
- 6-7. Accounting File Information
- 6-8. Filter Accounting Information
- 6-9. Accounting Gotchas
- 6-10. Accounting Using Banner Pages
- 7-1. Printer Pools and Load Sharing
- 7-2. Load Balancing Printcap
- 7-3. Load Balancing to Remote Queues
- 7-4. Printcap for Chooser
- 7-5. Chooser Program Operation
- 7-6. Filter Template in Perl
- 7-7. Choosing A Destintation
- 7-8. Chooser Exit Codes
- 8-1. Evil (BAD) Way
- 8-2. Not So Evil Way
- 8-3. Add Options Using :append_z
- 8-4. Option Modification
- 8-5. Incoming Control Filter
- 9-1. Hold Queues
- 9-2. All Hold Queues
- 9-3. Releasing Jobs for Printing
- 9-4. Releasing Jobs For Scheduled Print Run
- 9-5. Using Job Classes
- 9-6. Setting New Job Classes and Disabling Job Classes
- 9-7. Modifying Control File Using update_class
- 9-8. The update_class Filter
- 10-1. Using :bk (Berkeley Kompatible) Flag
- 11-1. Templates in Printcaps
- 11-2. Using lpc client all
- 11-3. Master User Printcap File, No Local Spooling
- 11-4. Master User Printcap File, Local Spooling
- 11-5. Master User Printcap File, No Local Spooling
- 11-6. All In One
- 11-7. Printcap Path Configuration Information
- 11-8. Example of Returned Printcap Value
- 12-1. Starting Screen
- 12-2. Printcap Entry Selection
- 12-3. Add A Printer
- 12-4. Option Specification
- 12-5. Advanced Options
- 12-6. ifhp Options
- 12-7. Saving Printcap Entry
- 12-8. Checkpc Results
Preface
A good cookbook will provide the reader not only with a set of recipes that sound delicious but also with a set of instructions that will allow novices to experts to prepare them. Of course, there are cookbooks for novices, cookbooks for experts, and then the gastronmic encyclopedias.
These Recipes for Printing are a collection of old favorites, not of the author, but of the hundreds of users of LPRng and other print spooling systems. They are not a complete discussion of the printing haute cuisine, but deal more with the preparation of the Minnesota Hot Dish. As I find from personal experience, you need to make a casserole for a family dinner far more often than to prepare mijotée de lentilles au lardons, dos de poisson-chat rôti, au vinaigre d'herbes for that one-time special dinner.
The various test files, scripts and examples in this document are also in the LPRng distribution in the /LPRng-xxx/UTILS directory.
Enjoy! Bon Appetite!
Acknowledgements
I would like to thank all of the LPRng users who so relentlessly tried an incredible number of permutations and combinations printers, software, and networks, and whose requests for just one more feature led to the development of the LPRng software.
Conventions
Many examples will show commands run by ordinary or privleged users. The prompt character will indicate the user:
Recipes and major examples will be show as:
Figure 1. lpq status
h110: {64} % lpq
Printer: lp@h110
Queue: no printable jobs in queue
Status: job 'cfA711h110.private' removed at 17:11:43.919
Filter_status: done at 17:11:43.823
Smaller sets of code or commands will be shown as:
Disclaimer
THIS DOCUMENTATION AND THE DESCRIBED SOFTWARE AND PROCEDURES IS PROVIDED BY THE AUTHORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS DOCUMENTATION, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Chapter 1. Introduction - The Basics and Variations
The LPRng print spooling system has the components shown in Figure 1-1. A program generates output and pipes it to the lpr application or the lpr application is used to print a file. The lpr application connects to the lpd print server over a network connection and then transfers the print job data and print options. The lpd server will store the job information Figure 1-2 in a spool directory and when the output device is available will transfer the job to the printing device.
Since the print job may not be in the appropriate format for the ouput device a filter program may be used to prepare the output data or perform special operations on the output device. Alternatively, the print job can be forwarded to another print spooler Figure 1-1, transferred directly to a TCP/IP network port.
As shown in Figure 1-2, the LPRng print spooler uses the /etc/printcap, /etc/lpd.conf, and /etc/lpd.perms, files to get its operational parameters. The the /etc/printcap file defines a set of spool queues, each of which holds print jobs. A print job if transfered to the print server as a a control file (cfAnnnHHHHHHH) and one or more data files (dfAnnnHHHHHHH dfBnnnHHHHHHH, etc). The information in the control file is extracted and stored in the hold file (hfAnnn) for the job. The hold file contains information such as the user name, file names, and printing options, while the data files contain the data to be printed.
Figure 1-3. Printcap
# Common configuration information
.common:sd=/var/spool/lpd/%P
:sh:mx=0:force_localhost
# forward to remote spooler
lp:cm=Default Printer
:tc=.common
:lp=raw@10.0.0.1
# legacy - :rp=raw:rm=10.0.0.1
# lp0 - open a device
lp0|aliasforlp0:cm=Parallel Port Printer:\
:tc=.common:lp=/dev/lpt0:
# lp1 - open a network connection
lp1:tc=.common:lp=10.0.0.14%9100
# lp2 - run a program
lp2:tc=.common:lp=|/usr/local/bin/smbprint
The /etc/printcap file format is very simple in appearance but complex in information. By convention, lines starting with # are comments; a printcap entry starts with the entry name followed by one or more aliases, followed by options.
The :tc option specifies a printcap entry for inclusion; there can be more than one entry and they are processed in order that they appear in the :tc list. The other options are processed after the :tc list; this means that the printcap options overide the ones from the :tc list. If a entry name starts with a period (.), then the LPRng system uses it only for :tc lists. This is similar to the use of hidden files, i.e. - files whose names start with a period are not displayed by the ls command.
Figure 1-4. lpd.conf Defaults File
# Purpose: always print banner, ignore lpr -h option # default ab@ (FLAG off) # Purpose: query accounting server when connected # default achk@ (FLAG off) # Purpose: accounting at end (see also af, la, ar, as) # default ae=jobend $H $n $P $k $b $t (STRING) # Purpose: name of accounting file (see also la, ar) # default af=acct (STRING) # Purpose: use long job number (0 - 999999) when a job is submitted # default longnumber@ (FLAG off) longnumber
The /etc/lpd.conf file can be used to override the set of default values for the print spooler or other printing applications. By the way, all of the LPRng options and their default values are defined in this file in the comments.
Figure 1-5. lpd.perm Permissions File
ACCEPT SERVICE=C SERVER REMOTEUSER=root,papowell ACCEPT SERVICE=C LPC=lpd,status,printcap REJECT SERVICE=C ACCEPT SERVICE=M SAMEHOST SAMEUSER ACCEPT SERVICE=M SERVER REMOTEUSER=root REJECT SERVICE=M DEFAULT ACCEPT
The /etc/lpd.perms file (Figure 1-5) is used by lpd to determine who is allowed to perform various operations. The format of this file is modelled on that of a packet filter. When a request is made, the file is scanned for matches; each match sets a success or fail condition. The success or fail of the last match (or the last default value) will determine whether or not to perform the operation.
The LPRng client applications lpr, lprm, lpq, and lpc use the /etc/lpd.conf, /etc/printcap and ${HOME}/.printap files (if they exist) (Figure 1-6). The values in the ${HOME}/.printcap file are used to override the values in the /etc/printcap file, and the first printcap entry in the ${HOME}/.printap file becomes the default printer for the user (see Figure 1-7).
Figure 1-7. ${HOME}/.printcap Information
# force your default printer # - forces first entry to be lp_out lp_out: # send everything to your secret server *:lp=%P@secret_server:force_localhost@ # combine the two above: lp|*:lp=%P@secret_server:force_localhost@ # and of course, you can specify extra lpr options # for those special purpose printers and total abuse landscape:lpr= -Zlandscape -Plp
1.1. Checking the Printing System
Figure 1-8. Using checkpc
h110: {1} % su
Password:
h110# checkpc
h110# checkpd -V
LPRng-3.7.10, Copyright 1988-2001 Patrick Powell, <papowell@lprng.com>
Checking for configuration files '/etc/lpd.conf'
found '/etc/lpd.conf', mod 0100644
Checking for printcap files '/etc/printcap'
found '/etc/printcap', mod 0100644
DaemonUID 1, DaemonGID 1
Using Config file '/etc/lpd.conf'
LPD lockfile '/var/run/lpd.515'
...
Checking printer 'lp'
Checking directory: '/var/spool/lpd/lp'
directory '/var'
directory '/var/spool'
directory '/var/spool/lpd'
directory '/var/spool/lpd/lp'
checking 'control.lp' file
checking 'status.lp' file
checking 'status' file
checking 'log' file
checking 'acct' file
The checkpc utility will read and parse the printcap file. It will report a zillion errors if something is wrong.
1.2. Fixing the Problems
Figure 1-9. Using checkpc -f
h110: {1} % checkpc
Warning - bad directory - /var/spool/lpd/lp
Warning - Printer_DYN 'lp' spool dir '/var/spool/lpd/lp' needs fixing
Warning - bad directory - /var/spool/lpd/lp0
Warning - Printer_DYN 'lp0' spool dir '/var/spool/lpd/lp0' needs fixing
h110: {2} % su
Password:
h110# checkpc -f
Warning - changing ownership '/var/spool/lpd/lp' to 1/1
Warning - changing ownership '/var/spool/lpd/lp' to 1/1
Warning - changing ownership '/var/spool/lpd/lp0' to 1/1
Warning - changing ownership '/var/spool/lpd/lp0' to 1/1
h110# exit
h110: {3} % checkpc
h110: {4} % checkpc
The checkpc -f (-f for fix) will make checkpc attempt create missing files, set permissions, and take basic corrective actions. If it fails, then you have probably a very bad /etc/printcap file.
Chapter 2. Simple Spooling
This section covers the basic facilities that you will probably encounter when trying to set up a print queue. We will start with a basic print queue and then run through the setup steps.
Figure 2-1. Basic Printcap Entry
# Common configuration information .common:sd=/var/spool/lpd/%P :sh:mx=0:force_localhost lp:cm=Default Printer, Forward to remote :tc=.common :lp=raw@10.0.0.1 # lp0 - open a device lp0:cm=Parallel Port Printer :tc=.common:lp=/dev/lpt0:
2.1. Setting Up The Print Queues
Figure 2-2. Run checkpc
h110: {1} % checkpc
Warning - bad directory - /var/spool/lpd/lp
Warning - Printer_DYN 'lp' spool dir '/var/spool/lpd/lp' needs fixing
Warning - bad directory - /var/spool/lpd/lp0
Warning - Printer_DYN 'lp0' spool dir '/var/spool/lpd/lp0' needs fixing
h110: {2} % su
Password:
h110# checkpc -f
Warning - changing ownership '/var/spool/lpd/lp' to 1/1
Warning - changing ownership '/var/spool/lpd/lp' to 1/1
Warning - changing ownership '/var/spool/lpd/lp0' to 1/1
Warning - changing ownership '/var/spool/lpd/lp0' to 1/1
h110# exit
h110: {3} % checkpc
h110: {4} % checkpc
First, you run checkpc -f. This will tell you if something is wrong with the printcap.
Figure 2-3. Check for Running Server
h110: {5} % lpc lpd
Printer 'lp@localhost' - cannot open connection - Connection refused
Make sure the remote host supports the LPD protocol
h110: {6} % su
Password:
h110# lpd
h110# lpc lpd
lpd server pid 6418 on h110.private
h110# exit
exit
h110: {7} % lpc lpd
lpd server pid 6418 on h110.private
Next, you make sure the lpd server is running, and if it is not, then you restart it.
Figure 2-4. Run lpq
h110: {373} % lpq -a
Printer: lp@h110
Queue: no printable jobs in queue
Printer: lp0@h110
Queue: no printable jobs in queue
You now make sure that you can get the print queue status.
Figure 2-5. Run lpc
h110: {374} % lpc stop lp lp0
Printer: lp@h110
lp@h110.private: stopped
Printer: lp0@h110
lp0@h110.private: stopped
h110: {375} % lpq -a
Printer: lp@h110 (printing disabled)
Queue: no printable jobs in queue
Printer: lp0@h110 (printing disabled)
Queue: no printable jobs in queue
Use lpc to disable printing.
Figure 2-6. Run lpr
h110: {376} % echo hi >/tmp/hi
h110: {377} % lpr /tmp/hi
h110: {378} % lpq
Printer: lp@h110 (printing disabled)
Queue: 1 printable job
Server: no server active
Rank Owner/ID Class Job Files Size Time
1 papowell@h110+445 A 445 /tmp/hi 3 17:40:51
h110: {379} % lpr -Plp0 /tmp/hi
h110: {380} % lpq -Plp0
Printer: lp0@h110 (printing disabled)
Queue: 1 printable job
Server: no server active
Rank Owner/ID Class Job Files Size Time
1 papowell@h110+449 A 449 /tmp/hi 3 17:41:05
Now try spooling a job.
Figure 2-7. Run lprm
h110: {381} % lprm
Printer lp@h110:
checking perms 'papowell@h110+445'
dequeued 'papowell@h110+445'
h110: {382} % lprm -Plp0
Printer lp0@h110:
checking perms 'papowell@h110+449'
dequeued 'papowell@h110+449'
Now try removing a job.
Figure 2-8. Enable Printing
h110: {383} % lpc enable lp lp0
Printer: lp@h110
lp@h110.private: enabled
Printer: lp0@h110
lp0@h110.private: enabled
Finally, enable printing.
2.2. Diagnostics for Spooling Problems
Figure 2-9. Using lpr -V
h110: {388} % lpr -V /tmp/hi
LPRng-3.7.10, Copyright 1988-2001 Patrick Powell, <papowell@lprng.com>
sending job 'papowell@h110+29' to lp@localhost
connecting to 'localhost', attempt 1
connected to 'localhost'
requesting printer lp@localhost
sending control file 'cfA029h110.private' to lp@localhost
completed sending 'cfA029h110.private' to lp@localhost
sending data file 'dfA029h110.private' to lp@localhost
completed sending 'dfA029h110.private' to lp@localhost
done job 'papowell@h110+29' transfer to lp@localhost
The first line of defense is to see what is happening when you try to spool a job. The lpr -V (-V for Verbose) will show a simple high level trace.
Figure 2-10. The lpr Options
h110: {389} % lpr -=
lpr: Illegal option '='
Usage: lpr [-Pprinter[@host]] [-A] [-B] [-Cclass] [-Fformat] [-G] [-Jinfo]
[-(K|#)copies] [-Q] [-Raccountname] [-Ttitle] [-Uuser[@host]] [-V]
[-Zoptions] [-b] [-m mailaddr] [-h] [-i indent] [-l] [-w width ] [-r]
[-Ddebugopt ] [--] [ filenames ... ]
-A - use authentication specified by AUTH environment variable
-B - filter files and reduce job to single file before sending
-C class - job class
-D debugopt - debugging flags
-F format - job format
-b,-l - binary or literal format
c,d,f,g,l,m,p,t,v are also format options
-G - filter individual job files before sending
-J info - banner and job information
-K copies, -# copies - number of copies
-P printer[@host] - printer on host
-Q - put 'queuename' in control file
-Raccntname - accounting information
-T title - title for 'pr' (-p) formatting
-U username - override user name (restricted)
-V - Verbose information during spooling
-X path - user specified filter for job files
-Y - connect and send to TCP/IP port (direct mode)
-Z options - options to pass to filter
-h - no header or banner page
-i indent - indentation
-k - do not use tempfile when sending to server
-m mailaddr - mail final status to mailaddr
-r - remove files after spooling
-w width - width to use
-- - end of options, files follow
filename '-' reads from STDIN
PRINTER, LPDEST, NPRINTER, NGPRINTER environment variables set default printer.
LPRng-3.7.10, Copyright 1988-2001 Patrick Powell, <papowell@lprng.com>
Use the -= option to see the available options.
Figure 2-11. Debug Options
h110: {392} % lpr -D=
debug usage: -D [ num | flag=num | flag=str | flag | flag@ | flag+N ]*
flags recognized: network[+N,@], database[+N,@], lpr[+N,@],
lpc[+N,@], lprm[+N,@], lpq[+N,@], log[+N,@],
test=num
The -D= option shows the debugging flags available.
Figure 2-12. The lpr -D1 Output
h110: {395} % lpr -D1 /tmp/hi >&/tmp/x
2001-10-18-05:29:05 [8052] Initialize: /dev/null fd 3
2001-10-18-05:29:05 [8052] initsetproctitle: using builtin
2001-10-18-05:29:05 [8052] lpr Setup_uid: OriginalEUID 0, OriginalRUID 1001
2001-10-18-05:29:05 [8052] lpr Setup_uid: OriginalEGID 1001, OriginalRGID 1001
2001-10-18-05:29:05.761 [8052] lpr Setup_configuration: starting, Allow_getenv 0
2001-10-18-05:29:05.761 [8052] lpr Setup_configuration: Configuration file '/etc/lpd.conf'
2001-10-18-05:29:05.761 [8052] lpr Setup_configuration: Require_configfiles_DYN '1'
2001-10-18-05:29:05.761 [8052] lpr Get_config: required '1', '/etc/lpd.conf'
2001-10-18-05:29:05.762 h110 [8052] lpr
Get_local_host: ShortHost_FQDN=h110, FQDNHost_FQDN=h110.private
2001-10-18-05:29:05.763 h110 [8052] lpr
Is_server 0, DaemonUID 1, DaemonGID 1, UID 0, EUID 0, GID 1001, EGID 1001
2001-10-18-05:29:05.763 h110 [8052] lpr
Setup_configuration: Host 'h110.private', ShortHost 'h110', user 'papowell'
...
The lpr -D1 (diagnostic level 1) shows a summary of the various steps taken to send the job. If you want more detail, try lpr -D2; or even lpr -D3;.
Figure 2-13. Using lpr -Dnetwork
h110: {400} % lpr -Dnetwork /tmp/hi
lp: getconnection: START host localhost, timeout 10, connection_type 1
lp: getconnection: fqdn found localhost.my.domain, h_addr_list count 1
lp: Link_dest_port_num: port 515 = 515
lp: getconnection: AGAIN port 808, min 512, max 1023, count 0, connects 0
lp: Link_dest_port_num: port 515 = 515
lp: getconnection: sock 3, src ip 127.0.0.1, port 808
lp: getconnection: dest ip 127.0.0.1, port 515
lp: getconnection: connection to 'localhost' socket 3, errormsg 'No Error'
lp: Link_send: host 'localhost' socket 3, timeout 6000
lp: Link_send: str '^Blp
', count 4, ack 0xbfbfc3d0
lp: Link_send: final status NO ERROR
lp: Link_send: host 'localhost' socket 3, timeout 6000
lp: Link_send: str '^B142 cfA065h110.private
', count 24, ack 0xbfbfbf90
lp: Link_send: final status NO ERROR
lp: Link_send: host 'localhost' socket 3, timeout 6000
lp: Link_send: str 'Hh110.private
Ppapowell
J/tmp/hi
CA
Lpapowell
Apapowell@h110+65
D2001-10-18-05:34:18.939
Qlp
N/tmp/hi
fdfA065h110.private
UdfA065h110.private
', count 143, ack 0xbfbfbf90
lp: Link_send: final status NO ERROR
lp: Link_send: host 'localhost' socket 3, timeout 6000
lp: Link_send: str '^C3 dfA065h110.private
', count 22, ack 0xbfbfbf24
lp: Link_send: final status NO ERROR
lp: Link_send: host 'localhost' socket 3, timeout 6000
lp: Link_send: str '', count 1, ack 0xbfbfbf24
lp: Link_send: final status NO ERROR
The lpr -Dnetwork (network diagnostic level 1) shows the network operations performed by lpr. If you want more detail, try lpr -Dnetwork+2 or even lpr -Dnetwork+3.
Figure 2-14. Debugging lpq
h110: {1} % lpq -=
lpq: Illegal option '='
usage: lpq [-aAclV] [-Ddebuglevel] [-Pprinter] [-tsleeptime]
-A - use authentication specified by AUTH environment variable
-a - all printers
-c - clear screen before update
-l - increase (lengthen) detailed status information
additional l flags add more detail.
-L - maximum detailed status information
-n linecount - linecount lines of detailed status information
-Ddebuglevel - debug level
-Pprinter - specify printer
-s - short (summary) format
-tsleeptime - sleeptime between updates
-V - print version information
h110: {2} % lpq -D1
2001-10-18-05:39:09 [8090] Initialize: /dev/null fd 3
2001-10-18-05:39:09 [8090] initsetproctitle: using builtin
2001-10-18-05:39:09 [8090] lpq Setup_uid: OriginalEUID 0, OriginalRUID 1001
...
h110: {3} % lpq -Dnetwork
lp: getconnection: START host localhost, timeout 10, connection_type 1
lp: getconnection: fqdn found localhost.my.domain, h_addr_list count 1
lp: Link_dest_port_num: port 515 = 515
lp: getconnection: AGAIN port 862, min 512, max 1023, count 0, connects 0
lp: Link_dest_port_num: port 515 = 515
lp: getconnection: sock 3, src ip 127.0.0.1, port 862
...
The lpq, lprm, and lpc applications also support the -= and -D (debug) options.
2.3. What Went Wrong With My Job?
Figure 2-15. Basic lpq Information
h110: {1} % lpr /tmp/hi
h110: {1} % lpq
Printer: lp@h110
Queue: 1 printable job
Server: pid 8741 active
Unspooler: pid 8742 active
Status: processing 'dfA740h110.private', size 3, format 'f',
IF filter 'ifhp' at 08:16:58.465
Filter_status: code = 10003, 'Warming Up' at 08:17:02.045
Rank Owner/ID Class Job Files Size Time
active papowell@h110+740 A 740 /tmp/hi 3 08:16:58
The first thing to do is check the status of your job with lpq. This will show the current jobs in the queue and lpd server. The Server value is the process that is responsible for sending jobs to the printer. It starts the Unspooler process that does the actual transfer to the remote system. Each time a job is processed a new Unspooler process is created. The Server process stays active until there is no further work to be done for the print queue.
Figure 2-16. Using the lpq -l Option
h110: {2} % lpq -l
Printer: lp@h110
Queue: 1 printable job
Server: pid 8741 active
Unspooler: pid 8742 active
Status: printing job 'papowell@h110+740' at 08:16:58.465
Status: processing 'dfA740h110.private', size 3, format 'f',
IF filter 'ifhp' at 08:16:58.465
Filter_status: getting end using 'pjl job/eoj' at 08:16:59.902
Filter_status: code = 10003, 'Warming Up' at 08:17:02.045
Rank Owner/ID Class Job Files Size Time
active papowell@h110+740 A 740 /tmp/hi 3 08:16:58
h110: {3} % lpq -lll
Printer: lp@h110
Queue: 1 printable job
Server: pid 8741 active
Unspooler: pid 8742 active
Status: accounting at start at 08:16:58.455
Status: opening device 'h14%9100' at 08:16:58.455
Status: printing job 'papowell@h110+740' at 08:16:58.465
Status: processing 'dfA740h110.private', size 3, format 'f',
IF filter 'ifhp' at 08:16:58.465
Filter_status: data sent at 08:16:59.902
Filter_status: sent job file at 08:16:59.902
Filter_status: getting end using 'pjl job/eoj' at 08:16:59.902
Filter_status: code = 10003, 'Warming Up' at 08:17:02.045
Rank Owner/ID Class Job Files Size Time
active papowell@h110+740 A 740 /tmp/hi 3 08:16:58
The lpq -l (longer) option increases the number of Status and Filter_status lines shown. These lines come from the status.%P and status files in the spool queue. Adding more -l options increases the amount of status shown.
Figure 2-17. Using the lpq -L Option
h110: {4} % lpq -L
Printer: lp@h110
Queue: 1 printable job
Server: pid 8741 active
Unspooler: pid 8742 active
Status: waiting for subserver to exit at 08:16:58.451
Status: subserver pid 8742 starting at 08:16:58.455
Status: accounting at start at 08:16:58.455
Status: opening device 'h14%9100' at 08:16:58.455
Status: printing job 'papowell@h110+740' at 08:16:58.465
Status: processing 'dfA740h110.private', size 3, format 'f',
IF filter 'ifhp' at 08:16:58.465
.....
Filter_status: decoded job type 'PCL' at 08:16:59.901
Filter_status: job type 'PCL' at 08:16:59.901
Filter_status: transferring 3 bytes at 08:16:59.902
Filter_status: 100 percent done at 08:16:59.902
Filter_status: data sent at 08:16:59.902
Filter_status: sent job file at 08:16:59.902
Filter_status: getting end using 'pjl job/eoj' at 08:16:59.902
Filter_status: code = 10003, 'Warming Up' at 08:17:02.045
.....
Rank Owner/ID Class Job Files Size Time
active papowell@h110+740 A 740 /tmp/hi 3 08:16:58
If you want to see LOTS of status, use lpq -L, which shows all the avilable status information.
Figure 2-18. Job Completion
h110: {5} % lpq
Printer: lp@h110
Queue: no printable jobs in queue
Status: job 'cfA740h110.private' removed at 08:18:07.776
Filter_status: done at 08:18:07.756
h110: {6} % lpq -lll
Printer: lp@h110
Queue: no printable jobs in queue
Status: printing job 'papowell@h110+740' at 08:16:58.465
Status: processing 'dfA740h110.private', size 3, format 'f',
IF filter 'ifhp' at 08:16:58.465
Status: IF filter 'ifhp' filter finished at 08:18:07.757
Status: printing finished at 08:18:07.757
Status: accounting at end at 08:18:07.774
Status: finished 'papowell@h110+740', status 'JSUCC' at 08:18:07.774
Status: subserver pid 8742 exit status 'JSUCC' at 08:18:07.775
Status: lp@h110.private: job 'cfA740h110.private' printed at 08:18:07.775
Status: job 'cfA740h110.private' removed at 08:18:07.776
Filter_status: transferring 3 bytes at 08:16:59.902
Filter_status: 100 percent done at 08:16:59.902
Filter_status: data sent at 08:16:59.902
Filter_status: sent job file at 08:16:59.902
Filter_status: getting end using 'pjl job/eoj' at 08:16:59.902
Filter_status: code = 10003, 'Warming Up' at 08:17:02.045
Filter_status: end of job detected at 08:18:06.457
Filter_status: pagecounter 105341 after 1 attempts at 08:18:07.756
Filter_status: pagecounter 105341, pages 1 at 08:18:07.756
Filter_status: done at 08:18:07.756
When your job is finished, you can use the lpq -lll options to see the final results of processing the job.
Figure 2-19. Summary Status Displays
h110: {7} % lpq -s
lp@h110 0 jobs
h110: {239} % lpq -s -a
lp@h110 0 jobs
lp0@h110 0 jobs (printing disabled)
h110: {8} % lpc status
Printer Printing Spooling Jobs Server Subserver Redirect Status/(Debug)
lp@h110 enabled enabled 0 none none
h110: {9} % lpc status all
Printer Printing Spooling Jobs Server Subserver Redirect Status/(Debug)
lp@h110 enabled enabled 0 none none
lp0@h110 disabled enabled 0 none none
h110: {10} % exit
The lpq -s (short status) shows a single summary line for status. Adding the -a (all queues) will print information for all the print queues.
The lpc status command queries the lpd server and reports the status of the queues operated by the lpd server. The lpd status all will show the status of all the print queues.
2.4. Diagnostics for lpd Problems
Figure 2-20. lpd Options
h110# lpd -=
lpd: Illegal option '='
usage: lpd [-FV] [-D dbg] [-L log]
Options
-D dbg - set debug level and flags
Example: -D10,remote=5
set debug level to 10, remote flag = 5
-F - run in foreground, log to STDERR
Example: -D10,remote=5
-L logfile - append log information to logfile
-V - show version info
h110# lpd -D=
debug usage: -D [ num | flag=num | flag=str | flag | flag@ | flag+N ]*
flags recognized: network[+N,@], database[+N,@], lpr[+N,@],
lpc[+N,@], lprm[+N,@], lpq[+N,@], log[+N,@],
test=num
The lpd server can be started in debug mode. However, the amount of information produced can be overwhelming. If you need to determine what is happening during initial connection, then you will have to do this.
Figure 2-21. Using lpd Debug Options
h110# lpd
h110# lpd -F -D1
2001-10-18-05:56:55 [8156] lpd Initialize: starting
...
2001-10-18-05:56:55.228 h110 [8156] lpd lpd: listening socket fd -6
Fatal error - Another print spooler is using TCP printer
port, possibly lpd process '8154'
2001-10-18-05:56:55.228 h110 [8156] lpd cleanup: done, exit(1)
h110# killall lpd
h110# lpd -F -D1
2001-10-18-05:57:05 [8158] lpd Initialize: starting
...
2001-10-18-05:57:05.800 h110 [8159] Waiting lpd: LOOP START
2001-10-18-05:57:05.800 h110 [8159] Waiting
lpd: starting select timeout 'yes', 600 sec, max_socks 7
---- other window
h110: {5} % lpr /tmp/hi
----
2001-10-18-05:57:44.341 h110 [8159] Waiting
lpd: select returned 1, error 'No Error'
2001-10-18-05:57:44.342 h110 [8159] Waiting
lpd: fd 5 readable
2001-10-18-05:57:44.342 h110 [8159] Waiting lpd: connection fd 8
2001-10-18-05:57:44.351 h110 [8159] Waiting Start_worker: fd 8
2001-10-18-05:57:44.356 h110 [8171] RECV lp: Fix_Rm_Rp_info: printer name 'lp'
2001-10-18-05:57:44.356 h110 [8171] RECV Reset_config: starting
2001-10-18-05:57:44.361 h110 [8171] RECV
lp: Select_pc_info: looking for 'lp', depth 0
...
This shows all of the information available about the printing operation. But it is jumbled all together. Usually you want to see just the information about a single spool queue.
Figure 2-22. Debugging Spool Queue
Printcap:
lp:sd=/var/spool/lpd/%P
:db=DebugOptions
db=1 - output to device level 1,
db=lpc db=lpq db=lpr db=lprm
- incoming lpc, lpq, lpr, lprm operations
Spool Queue: /var/spool/lpd/lp
Default Files - created by checkpc
control.%P - queue control (enable, disable...)
acct - accounting
status - filter status
status.%P - queue status
log - diagnostics
The checkpc program creates a standard set of files in each spool queue, including the log file. The :db=DebugOptions enables debugging output for the specified operation. Information is sent to the log file as soon as the print queue directory and debug flags for the spool queue are determined.
Figure 2-23. Setting Queue Debug Options
h110# vi /etc/printcap
set:
lp:...
:db=lpr
h110# lpc reread
lpd server pid 8200 on h110.private, sending SIGHUP
Edit the printcap. You can then use lpc reread to signal the lpd process to read the new /etc/printcap file.
Figure 2-24. log File
2001-10-18-06:11:30.349 h110 [8216] RECV
lp: Receive_job: debug 'lpr', Debug 0, DbgFlag 0x1000
2001-10-18-06:11:30.349 h110 [8216] RECV
lp: Receive_job: spooling_disabled 0
2001-10-18-06:11:30.349 h110 [8216] RECV
lp: Receive_job: sending 0 ACK for job transfer request
2001-10-18-06:11:30.349 h110 [8216] RECV
lp: Receive_job: from localhost.my.domain- getting file transfer line
2001-10-18-06:11:30.349 h110 [8216] RECV
lp: Receive_job: read from localhost.my.domain-
status 0 read 23 bytes '^B131 cfA215h110.private'
You can now use the log file to see the individual queue operations. The size of the log file is determined by the max_log_file_size (default is 1000Kbytes); when the log file exceeds this it is truncted to 25% of its maximum length.
Chapter 3. Printers
Figure 3-1. Printer Types
Printers: Cheap and Slow Ink Dispensers Not So Cheap Fast Printers Vintage Stuff On Sale Legacy Junk You Are Stuck With
Your office mate has just purchased a nice new $99 ink-jet printer and wants to use it on his office desktop. Your boss calls you in and tells you that the new PlattenPusher 5500 printer will arrive and it needs to be operational ASAP. And finally, you pick up a really good bargin on a used HP4mPlus laser printer, which all the folks on the LPRng mailing list recommend as the most reliable (and SLOW...) printer they ever used.
With your luck, probably all three happen on the same day. Welcome to the wonderful world of printers.
3.1. Interface
Figure 3-2. Interface Types
Connection:
Parallel port : write only (no status)
read/write (maybe you get status)
Serial port: read/write (status)
Network: serial port emulator
parallel port emulator
print spooler emulator
whacko interface
The type of interface on your printer is usually a function of the printer cost and speed. The low cost/low speed printers usually have a parallel port interface, while the higher cost/higher speed printers usually have both a parallel port and a network interface. Serial ports are usually found only on older model printers or those which have very special facilities.
3.2. Parallel Port
Some printers provide status information. In order to do this they need a bidirectional communications channel. The parallel port interface found on the original X86 PC/XT/ATX systems was write only. However, there were a couple of signals (OUT OF PAPER, ERROR, etc.) that provided status information to the computer system. By monitoring these signals the host computer could tell the user that there were problems with the printer. Fiendishly clever engineers discovered that they could use these signals to implement a bidirectional data channel over the parallel port. They could even put multiple devices (daisy chained) on the parallel port. Needless to say, of the hundreds of companies that used bidirectional parallel interfaces no two of them used the same method.
In a fit of desperation, the IEEE1284 standard (well, actually 3 standards) were developed to allow at least some sort of general consensus on how a bidirectional parallel port should work.
If you are interested in the details about Parallel Ports, see http://www.fapo.com/1284int.htm for a nice introduction, and the IEEE1394 Trade Association Home Page http://www.1394ta.com/ for pointers to other information.
The good news is that if your printer is IEEE1284 compliant, then it has a functional bidirectional interface that will return status and other information. The bad news, really bad news, and really really bad news is a) there is no software level API for using bidirectionality; b) the parallel IO drivers that exist differ from version to version; c) most of the time the status returned by the printer is useless anyways.
Given this set of problems I recommend that you:
-
Put only one device (your printer) on each parallel port.
-
Do not expect to get status information back from the printer.
As shown in Figure 1-1, the printcap entry for a parallel port (without a filter) is really simple. If your printer is offline or powered down, lpd will not be able to open the parallel port and you will see an endless list of error messages in the status file.
Figure 3-5. Loading Linux Parallel Port Driver
[papowell@h112 papowell]$ su Password: [root@h112 papowell]# echo </dev/lp0 [root@h112 papowell]# cd /proc/sys/dev/parport/ [root@h112 parport]# ls default parport0 [root@h112 parport]# cd parport0 [root@h112 parport0]# ls autoprobe autoprobe0 autoprobe1 autoprobe2 autoprobe3 base-addr devices dma irq modes spintime [root@h112 parport0]# cat autoprobe CLASS:PRINTER; MODEL:DESKJET 670C; MANUFACTURER:HEWLETT-PACKARD; DESCRIPTION:Hewlett-Packard DeskJet 670C; COMMAND SET:MLC,PCL,PML;
The Linux system uses loadable module drivers for the parallel ports and newer releases support the IEEE1284 device probe functions. You can use the command shown in Figure 3-5 to load the modules; the echo </dev/lp0 command tries to open the device in read mode, and then exits after reading nothing... which might suggest that you cannot get status from the device. If you have the /proc system installed, then you can see what the IEEE1284 probe function returned.
Figure 3-6. Parallel Port Problems
One Interrupt per Output Character
- One Interrupt per Blocks of Characters (DMA)
- Hope that DMA works
May operate by polling
Don't try to daisy chain devices
While you may think that you are getting a high throughput to the parallel port, in actual fact it may be very slow. In the worst case you will get a an interrupt for every character output. Even worse, sometimes the parallel port driver will spin block for a small period of time in the hopes that a character will be accepted by the printer so it can send another one. Finally, while many users have successfully daisy chained multiple devices, there is a resounding silence from them when asked about the success of simultaneous use of the devices.
To add insult to injury, some systems do not even support interrupts with their parallel port hardware. To do IO, they periodically poll the output device to see if it is ready to accept another character.
3.3. Network Ports
Most devices that support a network connection do so by either providing support for a print spooler interface (lpd) or by emulating a bidirectional connection to the printing device (socket or appsocket). If your printer provides status reporting, it is strongly recommended that you use the socket interface. This will allow you to monitor conditions reported by the printer.
Figure 3-8. Network Port Printcap
lp:lp=10.0.0.14%9100 :sd=/var/spool/lpd/%P lp2:lp=raw@10.0.0.14 :sd=/var/spool/lpd/%P # legacy :rp:rm support # :rp=raw:rm=10.0.0.14
The printcap for a network printer is shown in Figure 3-8. You can use the :rp:rm options if you want.
Figure 3-9. Benefits of Network Port Printcap
High Speed Low Error Rate (+ Error Detection) Long Distances Very low system overhead
Network port printing is effectively the highest speed. The TCP/IP protocol provides both flow control and error detection/correction. The printer and host system can be separated by quite large distances. Finally, the overhead of the TCP/IP connection is very low in terms of hardware and software.
If you have legacy systems that have serial or parallel ports, you can buy a Network Print Server box. These have a network interface and one or more parallel or serial port interfaces.
Table 3-1. Network Print Server Configuration Information
| Manufacturer | Model | RFC1179 Port Name (rp=XXX) | Send to TCP port |
|---|---|---|---|
| Cannon Printer | Cannon 460 PS, no hard drive | xjdirect | - Unknown if supported - |
| Cannon 460 PS hard drive | xjprint - print immediately,xjhold - print later | - Unknown if supported - | |
| Digital Products Inc. | NETPrint Print Server | PORTn, where n is port on server | - Unknown if supported - |
| Electronics For Imaging Inc. | Fiery RIP i series | normalq or urgentq | - Unknown if supported - |
| Fiery RIP XJ series | xjprint | - Unknown if supported - | |
| Fiery RIP XJ+ and SI series | print_Model, e.g. print_DocuColor | - Unknown if supported - | |
| Fiery models ZX2100, ZX3300, X2, X2e | - Unknown if supported - | ||
| Emulex Corp. | NETJet/NETQue print server | PASSTHRU | - Unknown if supported - |
| Extended Systems Inc. | ExtendNet Print Server | Printern, where n is port on server | - Unknown if supported - |
| Hewlett-Packard | JetDirect interface card | raw | 9100 |
| Hewlett-Packard | JetDirect Multiport Server | port 1 - raw1, port 2 - raw2, etc. | port 1 - 9100, port 2 - 9101, etc. |
| I-Data | Easycom 10 Printserver | par1 (parallel port 1) | - Unknown if supported - |
| Easycom 100 Printserver | LPDPRT1 | - Unknown if supported - | |
| IBM | Network Printer 12, 17, 24, and 24PS | PASS | - Unknown if supported - |
| Lantronix | EPS1, EPS2 | EPS_X_S1 (serial) port 1, EPS_X_P1 (parallel) port 2, etc. | 3001 (port 1), 3002 (port 2), etc. |
| QMS | Various Models | RAW | 35 (AppSocket) |
| Tektronix | Tektronix printer network cards | PS (PostScript), PCL (PCL), or AUTO(Auto-selection between PS, PCL, or HPGL). Not reliable. | 9100 (AppSocket on some models) |
| Rose Electronics | Microserve Print Servers | lp | 9100 |
| Xerox | Models 4505, 4510, 4517, 4520 | PASSTHRU | 2501 (AppSocket on some models) |
| Model 4512 | PORT1 | 10001 (programmable) | |
| Model N17 | RAW | 9100 | |
| Models N24 and N32 | RAW | 2000 | |
| Models 4900, 4915, 4925, C55 | PS | 2000 | |
| Document Centre DC220/230 | lp | - Unknown if supported - |
All company, brand, and product names are properties of their respective owners.
3.4. Sending To SMB (Samba, Microsoft) Printer, Novell, Appletalk
There are a wide number of other print spooling systems that have been developed over the years. Most of these use proprietary or arcane protocols to transfer files. These include the SMB protocol used by Microsoft, the Novell print spooler support, and the Apple corporation Appletalk (Copyright, Trademarks where applicable). These systems usually run on or with non-UNIX Operating Systems or on proprietary hardware. But over the years packages have been developed to interface to these systems.
Figure 3-12. Protocols, Packages, and Transfer Programs
Protocol Package Transfer Program SMB (CIFS) Samba smbclient + wrapper WWW: http://www.samba.org Novell Netware ncpfs (Linux) nprint + wrapper FTP: ftp.gwdg.de/pub/linux/misc/ncpfs (Also Linux Kernel Documentation/filesystems) Appletalk CAPS pap + wrapper WWW: http://sourceforge.net/projects/netatalk WWW: http://www.umich.edu/~rsug/netatalk
Each of these programs will transfer a print job to a remote system.
Figure 3-13. Printcap For Transfer Programs
lp: OR :lp=|/usr/local/lib/filters/smbprint OR :lp=|/usr/local/lib/filters/ncpprint OR :lp=|/usr/local/lib/filters/atalkprint # and the magic happens here :options=authfile="auth" host="h114" printer="lp" \ workgroup="ASTART" # or you can use #:options=share="//h114/lp" workgroup="ASTART" # See the LPRng/UTILS directory
You can specify a program to do the transfer to the remote host. The program will connect to the remote system and transfer STDIN to the printer. Errors will be written to STDERR and be put in the log by LPRng.
Figure 3-14. Samba smbclient Wrapper
#!/bin/sh
# configuration
smbclient=/usr/local/bin/smbclient
# get options from $PRINTCAP_ENTRY environment variable
PATH=/bin:/usr/bin:/usr/local/bin
options=`echo "${PRINTCAP_ENTRY}" | sed -n 's/:options=//p' `
echo OPTIONS $options >&2
if [ -n "$options" ] ; then
# paranoia: $options=`echo |perl -sp 's/[^\w\s,-+%="\']/ /'`
eval dummy=v `echo $options`;
fi
if [ "$oldversion" != "" -a "$authfile" != "" -a -f "$authfile" ] ; then
. $authfile;
$authfile=
fi
if [ "$translate" = "yes" ]; then
command="translate ; print -"
else
command="print -"
fi
if [ "$share" = "" ] ; then share="//$host/$printer" ; fi
echo $smbclient "$share" ${password:+password} -E \
${username:+-U} ${username:+username} ${hostip:+-I} \
$hostip -N ${workgroup:+-W} $workgroup \
${authfile:+-A} $authfile -c "$command" >&2
$smbclient "$share" ${password} -E \
${username:+-U} ${username} ${hostip:+-I} \
$hostip -N ${workgroup:+-W} $workgroup \
${authfile:+-A} $authfile -c "$command" >&2
The smbprint script is run with the $PRINTCAP_ENTRY environment variable set to the printcap (See Figure 3-15). The value is scanned for the :options line and then this line is used with eval to set variables. This is a slight security risk and you should not have any metacharacters in the options field, so you can optionally strain them out or you can trust in your editting skills in the printcap.
Figure 3-15. $PRINTCAP_ENTRY
lp: :lp=|/usr/local/lib/filters/smbprint :options=authfile="auth" host="h114" printer="lp" workgroup="ASTART"
There older versions of the smbclient required the user name and password on the command line. Unfortunately, the ps command would show the command line options, allowing users to see the password. Newer versions can read username and password from an authentication file. We can use either version by setting the oldversion option.
Finally, we echo the command for logging purposes (note that $password is not displayed and then run the smbclient command.
Figure 3-16. Novell and Appletalk Wrappers
ncpprint:
....
usercmd=""
if [ "$username" != "" ]; then
if [ "$password" != "" ]; then
usercmd="-U $username -P $password"
else
usercmd="-U $username -n"
fi
fi
nprint=/usr/bin/nprint -S $server -q $printer \
$usercmd -N - 2>/dev/null
atalkprint:
...
/usr/bin/pap -p "$username:$printer@$host"
This general template can also be used with the nprint command from the Novell Netware support package to send files to a Novel Netware printers and the pap command from the Netatalk package.
3.5. Serial Port
A serial line is usually bidirectional in operation, but there are very few printers that will return status information. The most notable exception to this are PostScript printers. If you use a serial port printer, it is absolutely essential that you implement flow control, and almost mandatory that you use hardware or RTS-CTS (Request To Send and Clear To Send) flow control. Finally, you need to have the serial line operate in RAW mode, so that the serial line driver does not abuse the output stream by introducing extraneous CR-LF sequences, and changing control characters such as ESC (Escape) into ^E sequences.
Figure 3-18. Serial Port Printcap
lp:lp=/dev/tty00 :stty=raw crtscts 19200 :sd=/var/spool/lpd/%P # optional Open Read Write #:rw
The :stty=... option is used to set line characteristics and takes a subset of the stty application parameters. You need to set the line speed and mode. If you need to get status information back from the printer, you should add the :rw (Open Read-Write) flag.
As you might suspect, the serial port is limited by the line speed. In addition, it has a higher rate of errors than you might expect. Most printers that use a serial port are for legacy purposes or have low speed and low data transfer requirements.
Chapter 4. Printer Job Formats
Figure 4-1. Page Description Lanaguages
Printer Input File Formats:
Postscript (Level 1, 2, 3)
PCL (PCL 5)
Text (Really Legacy PCL)
PJL
Configuration Specification for Job
- PostScript or PCL or HPGL or ...
Magic Mystery Proprietary Format
Most printers will only print jobs that have a particular format. These formats are called Page Description Languages. The most common are PostScript, PCL, and HPGL.
Figure 4-2. How To Identify Print Formats
Print Job Job Types Start of File File Type %! PostScript - Level Unknown %!PS-Adobe-1.0 PostScript - Level 1.0 %!PS-Adobe-2.0 PostScript - Level 2.0 %!PS-Adobe-2.1 PostScript - Level 2.0 %!PS-Adobe-3.0 PostScript - Level 2.0 \033%-12345X@PJL HP Printer Job Language data \033E\033 HP PCL printer data This ... Text
The type of file can be identified by looking at the content near the start of the file. This is how the file program determines the type of file Figure 1-1.
Figure 4-3. Using the file Application
h110: {1} % file *
Makefile: ASCII English text
atalkprint: Bourne shell script text executable
logo.gif: GIF image data, version 89a, 250 x 91,
one.pcl: HP PCL printer data
one.ps: PostScript document text conforming at level 3.0
one.pjl: HP Printer Job Language data
rewindstdin: ELF 32-bit LSB executable
testpage-a4.fig: FIG image text, version 3.1
testpage-a4.ps: PostScript document text conforming at level 2.0
testpage.fig: FIG image text, version 3.1
4.1. PostScript
Figure 4-4. One PostScript Page
%!PS-Adobe-3.0
%% one page (i.e. - a page with a 1 on it)
%%/Times-Roman
/Courier
findfont 200 scalefont setfont
72 300 moveto
(1) show
showpage
-- from PostScript Reference Manual 1986
Adobe (www.adobe.com)
This is an example of a PostScript File.
Figure 4-5. Generate One Page
h110: {1} % echo 1 |groff -Tps >/tmp/one.ps
h110: {2} % more /tmp/one.ps
%!PS-Adobe-3.0
%%Creator: groff version 1.16.1
%%CreationDate: Thu Oct 18 12:48:45 2001
%%DocumentNeededResources: font Times-Roman
%%DocumentSuppliedResources: procset grops 1.16 1
%%Pages: 1
%%PageOrder: Ascend
%%Orientation: Portrait
%%EndComments
%%BeginProlog
%%BeginResource: procset grops 1.16 1
/setpacking where{
pop
currentpacking
true setpacking
}if
/grops 120 dict dup begin
/SC 32 def
/A/show load def
/B{0 SC 3 -1 roll widthshow}bind def
The quick way to generate a test page is use groff. The groff -Tps outputs PostScript.
Figure 4-6. PostScript Document Structuring Conventions
Specifies how a PostScript print job should be formatted Divides the job up into a prolog and body The body contains pages - each page is in an individual section - each page is independant Various Levels - 3.0 with PostScript Level 3, etc.
Most document generation systems produce PostScript that meets the PostScript Document Structuring Convention. This allows you to massage PostScript Documents in several ways.
Figure 4-7. Tools for PostScript Document Manipulation
GhostScript - format conversion WWW: http://www.ghostscript.com PSUtils - utilities to massage PostScript by Angus Duggan FTP: ftp://ftp.dcs.ed.ac.uk/pub/ajcd/ WWW: http://www.dcs.ed.ac.uk/home/ajcd/psutils/ psbook rearranges pages into signatures psselect selects pages and page ranges pstops performs general page rearrangement and selection psnup put multiple pages per physical sheet of paper psresize alter document paper size epsffit fits an EPSF file to a given bounding box getafm (sh) outputs PostScript to retrieve AFM file from printer showchar (sh) outputs PostScript to draw a character with metric info fixdlsrps (perl) filter to fix DviLaser/PS output so that PSUtils works fixfmps (perl) filter to fix framemaker documents so that psselect etc. work fixmacps (perl) filter to fix Macintosh documents with saner version of md fixpsditps (perl) filter to fix Transcript psdit documents to work with PSUtils fixpspps (perl) filter to fix PSPrint PostScript so that psselect etc. work fixscribeps (perl) filter to fix Scribe PostScript so that psselect etc. work fixtpps (perl) filter to fix Troff Tpscript documents fixwfwps (perl) filter to fix Word for Windows documents for PSUtils fixwpps (perl) filter to fix WordPerfect documents for PSUtils fixwwps (perl) filter to fix Windows Write documents for PSUtils extractres (perl) filter to extract resources from PostScript files includeres (perl) filter to include resources into PostScript files psmerge (perl) hack script to merge multiple PostScript files
The combination of GhostScript and PSutils by Angus Duggan are a powerful combination.
Figure 4-8. Selection of Pages + 4up Printing
h110: {81} % psselect -p20-24 LPRng-HOWTO.ps | psnup -4 >p4up.ps
[20] [21] [22] [23] [24] Wrote 5 pages, 38404 bytes
[1] [2] Wrote 2 pages, 42769 bytes
Figure 4-10. End Of PostScript Job: ^D (CTRL-D)
^D is recognized as an 'end of job'
- causes reset of PostScript interpreter to defaults
^D%!PS-Adobe-3.0
...
^D
The Dreaded ^D at Start of Job - causes problems
Rest of job may be ignored!
Solution: strip off ^D at start
(ifhp = ps_eoj_at_start@)
The Dreaded ^D at End of Job - causes problems when
you are trying to massage postscript or append jobs
Solution: strip off ^D everywhere
(ifhp = ps_eoj_at_end@)
The ^D (CTRL-D) character is evil - it usually should not be put into raw files.
4.2. PCL
Figure 4-11. One PCL Page
^[E^[&u600D^[&l2A^[&l0O^[&l0E^[(0N^[(s1p0s0b4101T
^[(s24V^[*p655x942Y1^L^[E
Note: ^[ is ESC or \033
^[E is 'reset printer configuration'
This is an example of a PCL file. Note that the file starts with ^[E, or the reset configuration string. All PCL jobs should start with this so that the previous job does not cause a problem.
Figure 4-12. Generate One Page
h110: {1} % echo 1 | groff -Tlj4 >/tmp/one.pcl
h110: {2} % more
^[E^[&u600D^[&l2A^[&l0O^[&l0E^[(0N^[(s1p0s0b4101T
^[(s24V^[*p655x942Y1^L^[E
The quick way to generate a test page is use groff. The groff -Tlj4 outputs PCL level 5. Again, watch out for the evil ^D (CTRL-D) characters.
4.3. Printer Job Language (PJL) and PostScript, PCL
Figure 4-13. PJL Example
^[%-12345X@PJL @PJL RDYMSG DISPLAY = ":" @PJL USTATUSOFF @PJL USTATUS JOB = ON @PJL USTATUS DEVICE = ON @PJL USTATUS PAGE = ON @PJL USTATUS TIMED = 10 @PJL ENTER LANGUAGE = POSTSCRIPT ^D%! %!PS-Adobe-3.0 %% one page (i.e. - a page with a 1 on it) %%/Times-Roman /Courier findfont 200 scalefont setfont 72 300 moveto (1) show showpage ^D^[%-12345X@PJL @PJL RDYMSG DISPLAY = ":" @PJL EOJ NAME = ":" @PJL USTATUSOFF @PJL USTATUS JOB = ON @PJL USTATUS DEVICE = ON @PJL USTATUS PAGE = ON @PJL USTATUS TIMED = 10 @PJL RDYMSG DISPLAY = "Done: :" ^[%-12345X
Printer Job Language is used to set up configuration and other facilities for a printer. It can establish defaults for printing and provide direction to the printer on how to handle job items not specified by the PostScript or PCL language.
The PJL Reset command ^[%-12345X performs a Print Job lanaguage independent reset. This allows PJL to be used with PostScript or PCL.
4.4. Text Files
Figure 4-14. Text Files and The Jaggies
Text
- usually ASCII characters
The Dreaded Jaggies
File:
This is what you
see on the printer
Printer output:
This is what you
see on the printer
Text is usually just ASCII characters. Unix lines are terminated with new line (NL or \012, and when sent to a printer result in The Jaggies. You need to have carriage returns (CR or \015 added to the file. You need to fix this by one of several methods.
4.5. Magical Mystery Proprietary Format
Figure 4-16. Magical Mystery Formats
Magical Mystery Proprietary Format
- Usually a RASTER format
- legacy devices such as Versatek Plotters
- new super cheap InkJet Printers
The host system needs to do conversion to raster file
- Dirty Little Secret - some of these understand PCL Level 5
(monochrome) and are compatible with HP LaserJet 4.
You should try and see if your printer understands PCL. Try using GhostScript with the hpdj, ljet3 or ljet4.
Figure 4-17. GhostScript To The Rescue
h110: {64} % gs --help
AFPL Ghostscript 6.50 (2000-12-02)
Copyright (C) 2000 Aladdin Enterprises, Menlo Park, CA. All rights reserved.
Usage: gs [switches] [file1.ps file2.ps ...]
Most frequently used switches: (you can use # in place of =)
-dNOPAUSE no pause after page | -q `quiet', fewer messages
-g<width>x<height> page size in pixels | -r<res> pixels/inch resolution
-sDEVICE=<devname> select device | -dBATCH exit after last file
-sOutputFile=<file> select output file: - for stdout, |command for pipe,
embed %d or %ld for page #
Input formats: PostScript PostScriptLevel1 PostScriptLevel2 PDF
You can read PostScript level 1, 2, or PDF with this version of GhostScript.
Figure 4-18. GhostScript Devices
Available devices: x11 bbox x11alpha x11cmyk x11cmyk2 x11cmyk4 x11cmyk8 x11gray2 x11gray4 x11mono x11rg16x x11rg32x atx23 atx24 atx38 deskjet djet500 fs600 laserjet ljetplus ljet2p ljet3 ljet3d ljet4 ljet4d lp2563 oce9050 lj5mono lj5gray epswrite pswrite pdfwrite pxlmono pxlcolor bit bitrgb bitcmyk bmpmono bmpgray bmpsep1 bmpsep8 bmp16 bmp256 bmp16m bmp32b cgmmono cgm8 cgm24 jpeg jpeggray miff24 pcxmono pcxgray pcx16 pcx256 pcx24b pcxcmyk pcx2up pbm pbmraw pgm pgmraw pgnm pgnmraw ppm ppmraw pnm pnmraw pkm pkmraw pksm pksmraw plan9bm pngmono pnggray png16 png256 png16m psmono psgray psrgb faxg3 faxg32d faxg4 tiffcrle tiffg3 tiffg32d tiffg4 tifflzw tiffpack tiff12nc tiff24nc appledmp iwhi iwlo iwlq bj10e bj200 ccr cdeskjet cdjcolor cdjmono cdj500 cdj550 declj250 dnj650c lj4dith pj pjxl pjxl300 bjc600 bjc800 escp djet500c cljet5 cljet5pr cljet5c lj3100sw coslw2p coslwxl cp50 epson eps9mid eps9high ibmpro epsonc ap3250 st800 stcolor uniprint lj250 paintjet pjetxl hl7x0 imagen jetp3852 lbp8 lips3 lp8000 m8510 necp6 lq850 lxm5700m oki182 okiibm photoex sj48 t4693d2 t4693d4 t4693d8 tek4696 cfax dfaxlow dfaxhigh cif inferno mgrmono mgrgray2 mgrgray4 mgrgray8 mgr4 mgr8 sgirgb sunhmono cdj850 hpdj pcl3 hpdjplus hpdjportable hpdj310 hpdj320 hpdj340 hpdj400 hpdj500 hpdj500c hpdj510 hpdj520 hpdj540 hpdj550c hpdj560c hpdj600 hpdj660c hpdj670c hpdj680c hpdj690c hpdj850c hpdj855c hpdj870c hpdj890c hpdj1120c cdj970 stp nullpage
GhostScript converts PostScript to a wide range of output device formats. The interesting ones are ljet4, lj5mono, hpdj, and so forth. These are Ink Jet printers with various strange behaviors.
Figure 4-19. GhostScript Support
http://www.ghostscript.com http://www.cs.wisc.edu/~ghost http://www.cs.wisc.edu/~ghost/doc/printer.htm http://www.cs.wisc.edu/~ghost/doc/AFPL/devices.htm
The http://www.ghostscript.com site has links to just about everything concerned with GhostScript. the http://www.cs.wisc.edu/~ghost site mirrors much of this information. The printer.htm and devices.htm are good sources for information about printing.
4.6. Printing Test Pages
Figure 4-20. Printing Test Pages To Parallel Port
#!/bin/sh for i in one.pcl one.pjl one.ps ; do cat $i >/dev/lp0 done
The easiest way to print the test pages is to try them all. This is brutal, but you may need to do it at least once.
Figure 4-21. Using Netcat (nc)
nc - Netcat by Mudge http://www.avian.org/ ftp://ftp.lprng.com/pub/LPRng/TOOLS/netcat #!/bin/sh for i in one.pcl one.pjl one.ps ; do nc -w10 10.0.0.14 9100 <$i done h110: {453} % sh -x /tmp/testnc + nc -w10 -v -v 10.0.0.14 9100 h14.private [10.0.0.14] 9100 (jetdirect) open @PJL USTATUS DEVICE CODE=10003 DISPLAY="02 WARMING UP" ONLINE=TRUE ... @PJL USTATUS TIMED CODE=10001 DISPLAY="Done: papowell /" ONLINE=TRUE ^C
Netcat is a handy tool for testing network connections to a printer. You can also use it as a port mapper and find out what interesting ports are open on your print spooler box.
Chapter 5. Filters
A filter is responsible for converting the job data files to a format compatible with the printer, transfering the job to the printer, and monitoring for any problems.
Figure 5-2. Filter Specification in Printcap Entry
# LPRng lp: :filter=/.../filter # Legacy BSD (LPRng is backwards compatible) lp: # file 'format' is lower case letter X, filter is # 'Xf' option value, default format is 'f' so default # filter is 'if' :if=/.../filter :hf=/.../filter
The legacy BSD printing system required you to specify a filter for all input types. LPRng uses :filter to specify a default filter. Much more in line with modern printing.
Figure 5-3. Specifying Job Datafile Format
LPRng 'format' selection:
h110: {295} % lpr -Fx /tmp/hi
Legacy BSD 'format' selection:
h110: {295} % lpr -x /tmp/hi
Format 'b' (Binary) or 'l' (Literal)
for 'Passthrough' Operation - format 'l' is used
h110: {295} % lpr -l /tmp/hi
h110: {295} % lpr -b /tmp/hi
Control file example:
Hh110.private
J/tmp/hi
Lpapowell
N/tmp/hi
fdfA383h110.private <- first letter is format
UdfA383h110.private
The lpr -Fx (Filter x) option allows you to specify the filter type. Which, of course, if you use the :filter option is ignored. The Binary or Literal (-b or -l requests Pass Through treatment from the filter. The filter is still used, but it is passed a special flag.
In the control file, lines starting with lower case letters specify a format and the data file to print with the format.
Figure 5-4. Filter Execution Environment
lp:sd=/var/spool/lpd/%P
:filter=/filter
:lp=/dev/lp
Execution:
CWD is spool directory (/var/spool/lpd/lp)
Environment:
PATH=... - from /etc/lpd.conf
LD_LIBRARY_PATH=... - from /etc/lpd.conf
PRINTER=lp
PRINTCAP_ENTRY=lp: - printcap entry
:sd=/var/spool/lpd/lp with %P fixed up
:filter=/filter
:lp=/dev/lp
CONTROL=Aroot@h110+383 - job control file
CA
D2001-10-19-06:40:59.968
Hh110.private
J/tmp/hi
Lroot
Proot
Qlp
N/tmp/hi
fdfA383h110.private
UdfA383h110.private
HF=A=root@h110+383 - job control file
C=A
D=2001-10-19-06:40:59.968
H=h110.private
J=/tmp/hi
priority=B
transfername=cfA383h110.private
The PRINTCAP_PATH environment variable has new lines before every colon (:) so you can split it up easily in the filter. See Figure 3-14 for an example of this use. The CONTROL value is the job control file. The control file contains an image of the control file corresponding to the current job state. The HF value is the current hold file contents. This contains detailed information about processing and other options used by the lpd server. The output device is opened Read-Write if the :rw flag is set and it is a real device. Also, if the output is a filter or network connection then then the output is Read-Write.
Figure 5-5. Command Line Options
lp:sd=/var/spool/lpd/%P
:filter=/filter
:lp=/dev/lp
/filter <dfA383h110.private >/dev/lp
STDIN, STDOUT, STDERR to Filter_status
-CA -D2001-10-19-06:40:59.968 -Hh110.private -J/tmp/hi -Lroot -Qlp
From the control file
-Plp -Ff
Legacy and LPRng, -P printer, -F format
-n root -h h110.private -f dfA383h110.private
...
there are more lower case options than you want to think about
The filter command line options are really agressive due to history and feeping creaturism. All of the lines in the control file with a capital letter are passed as shown, the -F is used for the print job format, and the -c is set if the job format was l (Binary or Literal). The -f also is the name of the data file. STDIN is set to the data file and STDOUT to the output device or network connection. Just to make life interesting, the name of the accounting file (if it is specified in the printcap or if it has a default value) is passed as the last parameter.
Figure 5-6. Filter Exit Codes
Exit Code Action 0 (JSUCC) Successful, send filter output to printer 1 (JFAIL) Failed, retry later 2 (JABORT) Failed, do not retry, and Abort printing 3 (JREMOVE) Remove job 4 (JHOLD) Set job HOLD flag
The filter program exit codes can be used to control how the job is processed. The JSUCC (0) value is the normal successful exit code. The JFAIL (1) value is used to indicate some sort of temporary failure and the job should be retried again. The JABORT (2) is more serious, and indicates some system error. The job should not be retried and printing should stop. The JREMOVE (3) code simply removes the job. This is useful if the job is unprintable. Finally, the JHOLD sets the job HOLD flag. The job will not be released for printing until the lpc release command releases it.
Figure 5-7. Solid As A Rock Filter Operation
Filter:
- examines input format using file
- decides if file format is compatible with printer
if not, can run a conversion program to convert
the output.
- initializes printer by sending magic cookies to it
magic cookies depend on particular device, model, etc.
- transfers output to printer, optionally inserting various
control codes, CR -> CR/LF
- if printer can reports status, then gets status as it does
the transfer operation.
- after transferring job, sends more magic cookies to tell
printer that job is over
- monitors printer for error status
- exits with an appropriate error code telling exactly what
problems (if any) were encountered.
This is what a real filter should do. Note that it appears to be obvious that you would need to do all this.
Figure 5-8. Solid As A Used Paper Coffee Filter Operation
Filter:
- Tosses job at GhostScript for conversion, sets
GhostScript output to STDOUT
- Returns GhostScript exit status
OK, I am being a bit harsh. But this is not too far from the truth. Most filter packages are somewhere between the two extremes.
5.1. Writing Your Own Filter
If you want to write your own filter you can start with the following simple examples. In practice you have two choices: Perl or sh. The first in a filter is to get the various environment and option values. We will write a simple filter that converts PostScript files into 4 up PostScript files.
Figure 5-9. Filter Template in perl
#!/usr/bin/perl
use Getopt::Std;
my $debug = 0; # always... sigh...
my(%opt, @pc, %options);
# get command line options
getopts( 'A:B:C:D:E:F:G:H:I:J:K:L:M:N:O:P:Q:R:T:S:U:V:W:X:Y:Z:'
. 'a:b:cd:e:f:g:h:i:j:k:l:m:n:o:p:q:r:t:s:u:v:w:x:y:z:', \%opt );
while( @ARGV ){ $opt{acct} = pop @ARGV ; };
# split up the PRINTCAP_ENTRY environment variable value
@pc = split /\n\s*:/s, ($ENV{PRINTCAP_ENTRY} || "");
shift @pc; # throw way first entry field, printer name
# set the options
foreach (@pc){ # set the options values
if( /^(.+)=(.*)/ ){ $options{$1} = $2;
} elsif ( /^(.+)@/ ){ $options{$1} = 0;
} else { $options{$_} = 1; }
}
if( $debug ){ # for those interested
my $s = "";
foreach my $v (sort keys %options ){ $s .= "$v='$options{$v}',"; }
print STDERR "Printcap: '$s'\n"; $s="";
foreach my $v (sort keys %opt){ $s .= "$v='$opt{$v}',"; }
print STDERR "Args: '$s'\n";
}
This example shows how to get the various environment variables and command line options and put them into handy hashes for easy access. You should note the special treatment of the -c option and the arguments at the end of the command line. The last argument is the name of the accounting file (if any).
Figure 5-10. How To Determine The Type of Job File
my $file = `/usr/bin/file -`; # we find the file type
chomp $file;
print STDERR "File: '$file'\n" if $debug; # show the file type
sysseek STDIN,0,0 or die "cannot seek STDIN - $!"; # rewind to start of file
my $is_postscript = ($file =~ /PostScript/i);
print STDERR "Postscript: '$is_postscript'\n" if $debug; # show the file type
if( $is_postscript ){
my $status = system "/usr/local/bin/psnup", "-4";
if( $status ){
print STDERR "psnup failed - $!\n";
exit 1;
}
exit 0;
}
while( <STDIN> ){ print };
exit 0;
To determine the file type we use the file application. This reads the first part of the input file and then writes out the determined file type on its STDOUT. We check to see if the file is a PostScript file and then run the psnup command. If it is not, then we simply write copy STDIN to STDOUT.
Figure 5-11. Printcap for Filter
nup:force_localhost :filter=/usr/local/libexec/filters/nup :sd=/var/spool/lpd/%P :lp=lp@localhost (Don't forget to run checkpc!)
We set make a printcap entry. Note the use of force_localhost to make sure that the print jobs are sent to the right print queue! The filter output will then be sent to lp@localhost for final printing.
Figure 5-12. Using Filter With $debug=1
Status: processing 'dfA946h110.private', size 145, format 'f',
IF filter 'nup' at 07:27:30.938
Status: IF filter 'nup' filter msg - 'Printcap: 'cm='Class Test Printer 1',....
Status: IF filter 'nup' filter msg - 'Args: 'A='papowell@h110+946',C='A',....
Status: IF filter 'nup' filter msg - 'File: 'standard input: PostScript document'
at 07:27:30.938
Status: IF filter 'nup' filter msg - 'Postscript: '1'' at 07:27:30.938
Status: IF filter 'nup' filter msg - 'Wrote 0 pages, 1775 bytes' at 07:27:30.940
Status: IF filter 'nup' filter finished at 07:27:30.941
Status: sending job 'papowell@h110+946' to lp@localhost at 07:27:30.943
Figure 5-12 shows the status output when we set the $debug=1. This is recommended when you are testing your filters.
Figure 5-13. Using Filter With $debug=0
Status: processing 'dfA021h110.private', size 145, format 'f', IF filter 'nup' at 07:38:22.416 Status: IF filter 'nup' filter msg - 'Wrote 0 pages, 1775 bytes' at 07:38:22.472 Status: IF filter 'nup' filter finished at 07:38:22.473 Status: sending job 'papowell@h110+21' to t6@localhost at 07:38:22.475
Figure 5-13 shows the status output when we set the $debug=0. As you can see, it is less chatty and just as informative to most users.