diff --git a/en_US.ISO8859-1/books/handbook/printing/chapter.xml b/en_US.ISO8859-1/books/handbook/printing/chapter.xml index ca73704d6f..91f367ecc7 100644 --- a/en_US.ISO8859-1/books/handbook/printing/chapter.xml +++ b/en_US.ISO8859-1/books/handbook/printing/chapter.xml @@ -1,5033 +1,1142 @@ - - Printing + + + + Printing + - SeanKellyContributed by - - - - JimMockRestructured and updated by + + + Warren + Block + Originally contributed by + - + Putting information on paper is a vital function, despite many + attempts to eliminate it. Printing has two basic components. The + data must be delivered to the printer, and must be in a form that + the printer can understand. - - Synopsis + + Quick Start - LPD spooling system - printing + Basic printing can be set up quickly. The printer must be + capable of printing plain ASCII text. For + printing to other types of files, see + . - &os; can be used to print with a wide variety of printers, - from the oldest impact printer to the latest laser printers, - and everything in between, allowing you to produce high-quality - printed output from the applications you run. + + + Create a directory to store files while they are being + printed: - &os; can also be configured to act as a print server on a - network; in this capacity &os; can receive print jobs from a - variety of other computers, including other &os; computers, - &windows; and &macos; hosts. &os; will ensure that one job - at a time is printed, and can keep statistics on which users - and machines are doing the most printing, produce - banner pages showing whose printout is whose, - and more. + &prompt.root; mkdir -p /var/spool/lpd/lp +&prompt.root; chown daemon:daemon /var/spool/lpd/lp +&prompt.root; chmod 770 /var/spool/lpd/lp + - After reading this chapter, you will know: + + As root, + create /etc/printcap with these + contents: - - - How to configure the &os; print spooler. - + lp:\ + :lp=/dev/unlpt0:\ + :sh:\ + :mx#0:\ + :sd=/var/spool/lpd/lp:\ + :lf=/var/log/lpd-errs: - - How to install print filters, to handle special print - jobs differently, including converting incoming documents - to print formats that your printers understand. - + + + This line is for a printer connected to a + USB port. - - How to enable header, or banner pages on your - printout. - + For a printer connected to a parallel or + printer port, use: - - How to print with printers connected to other - computers. - + :lp=/dev/lpt0:\ - - How to print with printers connected directly to the - network. - + For a printer connected directly to a network, + use: - - How to control printer restrictions, including limiting - the size of print jobs, and preventing certain users from - printing. - + :lp=:rm=network-printer-name:rp=raw:\ - - How to keep printer statistics, and account for printer - usage. - + Replace + network-printer-name with the + DNS host name of the network + printer. + + + - - How to troubleshoot printing problems. - - + + Enable lpd by editing + /etc/rc.conf, adding this line: - Before reading this chapter, you should: + lpd_enable="YES" - - - Know how to configure and install a new kernel - (). - - + Start the service: + + &prompt.root; service lpd start +Starting lpd. + + + + Print a test: + + &prompt.root; printf "1. This printer can print.\n2. This is the second line.\n" | lpr + + + If both lines do not start at the left border, but + stairstep instead, see + . + + + Text files can now be printed with + lpr. Give the filename on the command + line, or pipe output directly into + lpr. + + &prompt.user; lpr textfile.txt +&prompt.user; ls -lh | lpr + + - - Introduction + + Printer Connections - In order to use printers with &os; you may set them up to - work with the Berkeley line printer spooling system, also known - as the LPD spooling system, or just - LPD. It is the standard printer - control system in &os;. This chapter introduces - LPD and will guide you through its - configuration. + Printers are connected to computer systems in a variety of + ways. Small desktop printers are usually connected directly to + computer's USB port. Older printers are + connected to a parallel or printer port. Some + printers are directly connected to a network, making it easy for + multiple computers share them. A few printers use a much less + common serial port connection. - If you are already familiar with - LPD or another printer spooling - system, you may wish to skip to section Basic Setup. + &os; can communicate with all of these types of + printers. - LPD controls everything about - a host's printers. It is responsible for a number of - things: - - - - It controls access to attached printers and printers - attached to other hosts on the network. - - - - It enables users to submit files to be printed; these - submissions are known as jobsprint jobs. - - - - It prevents multiple users from accessing a printer at - the same time by maintaining a queue - for each printer. - - - - It can print header pages (also - known as banner or - burst pages) so users can easily find - jobs they have printed in a stack of printouts. - - - - It takes care of communications parameters for printers - connected on serial ports. - - - - It can send jobs over the network to a - LPD spooler on another - host. - - - - It can run special filters to format jobs to be printed - for various printer languages or printer - capabilities. - - - - It can account for printer usage. - - - - Through a configuration file - (/etc/printcap), and by providing the - special filter programs, you can enable the - LPD system to do all or some subset - of the above for a great variety of printer hardware. - - - Why You Should Use the Spooler - - The spooler still provides benefit on a single-user system - and should be used because: - - - - LPD prints jobs in the - background; you do not have to wait for data to be copied - to the printer. - + + + USB - LPD can conveniently run - a job to be printed through filters to add date/time - headers or convert a special file format (such as a &tex;&tex; - DVI file) into a format the printer will understand. - You will not have to do these steps manually. + USB printers can be connected to + any available USB port on the + computer. + + When &os; detects a USB printer, + two device entries are created: + /dev/ulpt0 and + /dev/unlpt0. Data sent to either + device will be relayed to the printer. After each print + job, ulpt0 resets the + USBport. Resetting the port can cause + problems with some printers, so the + unlpt0 device is used instead. + unlpt0 does not reset the USB port at + all. + + + + Parallel (IEEE-1284) - Many free and commercial programs that provide a print - feature usually expect to talk to the spooler on your - system. By setting up the spooling system, you will more - easily support other software you may later add or already - have. + The parallel port device is + /dev/lpt0. This device appears + whether a printer is attached or not, it is not + autodetected. + + Vendors have largely moved away from these + legacy ports, and many computers no longer + have them. Adapters can be used to connect a parallel + printer to a USB port. With such an + adapter, the printer can be treated as if it were actually + a USB printer. Devices called + print servers can also be used to + connect parallel printers directly to a network. - + + + + Serial (RS-232) + + + Serial ports are another legacy port, rarely used for + printers except in certain niche applications. Cables, + connectors, and required wiring vary widely. + + For serial ports built into a motherboard, the serial + device name is /dev/cuau0 or + /dev/cuau1. Serial + USB adapters can also be used, and + these will appear as + /dev/cuaU0. + + Several communication parameters must be known to + communicate with a serial printer. The most important are + baud rate and + parity. Values vary, but typical + serial printers often use a baud rate of 9600 and no + parity. + + + + + Network + + + Network printers are connected directly to the local + computer network. + + The DNS hostname of the printer + must be known. If the printer is assigned a dynamic + address by DHCP, DNS + should be dynamically updated so that the host name always + has the correct IP address. Network + printers are often given static IP + addresses to avoid this problem. + + Most network printers understand print jobs sent with + the LPD protocol. A print queue name + can also be specified. Some printers process data + differently depending on which queue is used. For + example, a raw queue prints the data + unchanged, while the text queue adds + carriage returns to plain text. + + Many network printers can also print data sent + directly to port 9100. + + + + + + Summary + + Wired network connections are usually the easiest to + set up and give the fastest printing. For direct connection + to the computer, USB is preferred for speed + and simplicity. Parallel connections work but have + limitations on cable length and speed. Serial connections are + more difficult to configure. Cable wiring differs between + models, and communication parameters like baud rate and parity + bits must add to the complexity. Fortunately, serial printers + are rare. - - Basic Setup + + Common Page Description Languages - To use printers with the LPD - spooling system, you will need to set up both your printer - hardware and the LPD software. This - document describes two levels of setup: + Data sent to a printer must be in a language that the + printer can understand. These languages are called Page + Description Languages, or PDLs. - - - See section Simple - Printer Setup to learn how to connect a printer, - tell LPD how to communicate with - it, and print plain text files to the printer. - - - - See section Advanced - Printer Setup to learn how to print a variety of - special file formats, to print header pages, to print across - a network, to control access to printers, and to do printer - accounting. - - - - - Simple Printer Setup - - This section tells how to configure printer hardware - and the LPD software to use the - printer. It teaches the basics: - - - - Section Hardware - Setup gives some hints on connecting the printer - to a port on your computer. - + + + ASCII - Section Software - Setup shows how to set up the - LPD spooler configuration - file (/etc/printcap). + Plain ASCII text is the simplest + way to send data to a printer. Characters correspond one + to one with what will be printed: an A + in the data prints an A on the page. + Very little formatting is available. There is no way to + select a font or proportional spacing. The forced + simplicity of plain ASCII means that + text can be printed straight from the computer with little + or no encoding or translation. The printed output + corresponds directly with what was sent. + + Some inexpensive printers cannot print plain + ASCII text. This makes them more + difficult to set up, but it is usually still + possible. - - - If you are setting up a printer that uses a network - protocol to accept data to print instead of a computer's local - interfaces, see Printers With - Networked Data Stream Interfaces. - - Although this section is called Simple Printer - Setup, it is actually fairly complex. Getting the - printer to work with your computer and the - LPD spooler is the hardest part. - The advanced options like header pages and accounting are - fairly easy once you get the printer working. - - - Hardware Setup - - This section tells about the various ways you can - connect a printer to your PC. It talks about the kinds of - ports and cables, and also the kernel configuration you may - need to enable &os; to speak to the printer. - - If you have already connected your printer and have - successfully printed with it under another operating system, - you can probably skip to section Software Setup. - - - Ports and Cables - - Printers sold for use on PC's today generally come - with one or more of the following three interfaces: - - - - Serialprintersserial interfaces, also known - as RS-232 or COM ports, use a serial port - on your computer to send data to the printer. Serial - interfaces are common in the computer industry and - cables are readily available and also easy to - construct. Serial interfaces sometimes need special - cables and might require you to configure somewhat - complex communications options. Most PC serial ports - have a maximum transmission rate of 115200 bps, - which makes printing large graphic print jobs with - them impractical. - - - - Parallelprintersparallel interfaces use a - parallel port on your computer to send data to the - printer. Parallel interfaces are common in the PC - market and are faster than RS-232 serial. Cables are - readily available but more difficult to construct by - hand. There are usually no communications options - with parallel interfaces, making their configuration - exceedingly simple. - - Parallel interfaces are sometimes known as - Centronicscentronicsparallel printers interfaces, named after the - connector type on the printer. - - - - USBprintersUSB interfaces, named for the Universal Serial - Bus, can run at even faster speeds than parallel or - RS-232 serial interfaces. Cables are simple and - cheap. USB is superior to RS-232 Serial and to - Parallel for printing, but it is not as well supported - under &unix; systems. A way to avoid this problem is - to purchase a printer that has both a USB interface - and a Parallel interface, as many printers do. - - - - In general, Parallel interfaces usually offer just - one-way communication (computer to printer) while serial - and USB gives you two-way. Newer parallel ports (EPP and - ECP) and printers can communicate in both directions under - &os; when a IEEE-1284-compliant cable is used. - - PostScript - - Two-way communication to the printer over a parallel - port is generally done in one of two ways. The first - method uses a custom-built printer driver for &os; that - speaks the proprietary language used by the printer. This - is common with inkjet printers and can be used for - reporting ink levels and other status information. The - second method is used when the printer supports - &postscript;. - - &postscript; jobs are actually programs sent to the - printer; they need not produce paper at all and may return - results directly to the computer. &postscript; also uses - two-way communication to tell the computer about problems, - such as errors in the &postscript; program or paper jams. - Your users may be appreciative of such information. - Furthermore, the best way to do effective accounting with - a &postscript; printer requires two-way communication: - you ask the printer for its page count (how many pages - it has printed in its lifetime), then send the user's job, - then ask again for its page count. Subtract the two - values and you know how much paper to charge to the - user. - - - - Parallel Ports - - To hook up a printer using a parallel interface, - connect the Centronics cable between the printer and the - computer. The instructions that came with the printer, - the computer, or both should give you complete - guidance. - - Remember which parallel port you used on the computer. - The first parallel port is - ppc0 to &os;; - the second is ppc1, and so on. The - printer device name uses the same scheme: - /dev/lpt0 for - the printer on the first parallel ports etc. - - - - Serial Ports - - To hook up a printer using a serial interface, connect - the proper serial cable between the printer and the - computer. The instructions that came with the printer, - the computer, or both should give you complete - guidance. - - If you are unsure what the proper serial - cable is, you may wish to try one of the - following alternatives: - - - - A modem cable connects each - pin of the connector on one end of the cable straight - through to its corresponding pin of the connector on - the other end. This type of cable is also known as a - DTE-to-DCE cable. - - - - A null-modem cablenull-modem cable connects - some pins straight through, swaps others (send data to - receive data, for example), and shorts some internally - in each connector hood. This type of cable is also - known as a DTE-to-DTE cable. - - - - A serial printer cable, - required for some unusual printers, is like the - null-modem cable, but sends some signals to their - counterparts instead of being internally - shorted. - - - - baud rate - parity - flow control - protocol - You should also set up the communications parameters - for the printer, usually through front-panel controls or - DIP switches on the printer. Choose the highest - bps (bits per second, sometimes - baud rate) that both your computer - and the printer can support. Choose 7 or 8 data bits; - none, even, or odd parity; and 1 or 2 stop bits. Also - choose a flow control protocol: either none, or XON/XOFF - (also known as in-band or - software) flow control. Remember these - settings for the software configuration that - follows. - - - - - Software Setup - - This section describes the software setup necessary - to print with the LPD spooling - system in &os;. - - Here is an outline of the steps involved: - - - - Configure your kernel, if necessary, for the port - you are using for the printer; section Kernel Configuration - tells you what you need to do. - - - - Set the communications mode for the parallel port, - if you are using a parallel port; section Setting the - Communication Mode for the Parallel Port gives - details. - - - - Test if the operating system can send data to the - printer. Section Checking Printer - Communications gives some suggestions on how to - do this. - - - - Set up LPD for the - printer by modifying the file - /etc/printcap. You will find out - how to do this later in this chapter. - - - - - Kernel Configuration - - The operating system kernel is compiled to work with - a specific set of devices. The serial or parallel - interface for your printer is a part of that set. - Therefore, it might be necessary to add support for an - additional serial or parallel port if your kernel is not - already configured for one. - - To find out if the kernel you are currently using - supports a serial interface, type: - - &prompt.root; grep sioN /var/run/dmesg.boot - - Where N is the number of - the serial port, starting from zero. If you see output - similar to the following: - - sio2 at port 0x3e8-0x3ef irq 5 on isa -sio2: type 16550A - - then the kernel supports the port. - - To find out if the kernel supports a parallel - interface, type: - - &prompt.root; grep ppcN /var/run/dmesg.boot - - Where N is the number of - the parallel port, starting from zero. If you see output - similar to the following: - - ppc0: <Parallel port> at port 0x378-0x37f irq 7 on isa0 -ppc0: SMC-like chipset (ECP/EPP/PS2/NIBBLE) in COMPATIBLE mode -ppc0: FIFO with 16/16/8 bytes threshold - - then the kernel supports the port. - - You might have to reconfigure your kernel in order - for the operating system to recognize and use the parallel - or serial port you are using for the printer. - - To add support for a serial port, see the section on - kernel configuration. To add support for a parallel port, - see that section and the section that - follows. - - - - - Setting the Communication Mode for the Parallel - Port - - When you are using the parallel interface, you can - choose whether &os; should use interrupt-driven or polled - communication with the printer. The generic printer - device driver (&man.lpt.4;) on &os; - uses the &man.ppbus.4; system, which controls the port - chipset with the &man.ppc.4; driver. - - - - The interrupt-driven method - is the default with the GENERIC kernel. With this - method, the operating system uses an IRQ line to - determine when the printer is ready for data. - - - - The polled method directs the - operating system to repeatedly ask the printer if it is - ready for more data. When it responds ready, the kernel - sends more data. - - - - The interrupt-driven method is usually somewhat faster - but uses up a precious IRQ line. Some newer HP printers - are claimed not to work correctly in interrupt mode, - apparently due to some (not yet exactly understood) timing - problem. These printers need polled mode. You should use - whichever one works. Some printers will work in both - modes, but are painfully slow in interrupt mode. - - You can set the communications mode in two ways: by - configuring the kernel or by using the &man.lptcontrol.8; - program. - - To set the communications mode by configuring - the kernel: - - - - Edit your kernel configuration file. Look for - an ppc0 entry. If you are setting up - the second parallel port, use ppc1 - instead. Use ppc2 for the third - port, and so on. - - - - If you want interrupt-driven mode, edit the - following line: - - hint.ppc.0.irq="N" - - in the /boot/device.hints - file and replace N with - the right IRQ number. The kernel configuration file - must also contain the &man.ppc.4; driver: - - device ppc - - - - If you want polled mode, remove in your - /boot/device.hints file, the - following line: - - hint.ppc.0.irq="N" - - In some cases, this is not enough to put the - port in polled mode under &os;. Most of - time it comes from &man.acpi.4; driver, this latter - is able to probe and attach devices, and therefore, - control the access mode to the printer port. You - should check your &man.acpi.4; configuration to - correct this problem. - - - - - - Save the file. Then configure, build, and install - the kernel, then reboot. See kernel configuration - for more details. - - - - To set the communications mode with - &man.lptcontrol.8;: - - - - Type: - - &prompt.root; lptcontrol -i -d /dev/lptN - - to set interrupt-driven mode for - lptN. - - - - Type: - - &prompt.root; lptcontrol -p -d /dev/lptN - - to set polled-mode for - lptN. - - - - You could put these commands in your - /etc/rc.local file to set the mode each - time your system boots. See &man.lptcontrol.8; for more - information. - - - - Checking Printer Communications - - Before proceeding to configure the spooling system, you - should make sure the operating system can successfully send - data to your printer. It is a lot easier to debug printer - communication and the spooling system separately. - - To test the printer, we will send some text to it. For - printers that can immediately print characters sent to them, - the program &man.lptest.1; is perfect: it generates all 96 - printable ASCII characters in 96 lines. - - PostScript - For a &postscript; (or other language-based) printer, we - will need a more sophisticated test. A small &postscript; - program, such as the following, will suffice: - - %!PS -100 100 moveto 300 300 lineto stroke -310 310 moveto /Helvetica findfont 12 scalefont setfont -(Is this thing working?) show -showpage - - The above &postscript; code can be placed into a file - and used as shown in the examples appearing in the following - sections. - - PCL - - When this document refers to a printer language, it - is assuming a language like &postscript;, and not Hewlett - Packard's PCL. Although PCL has great functionality, you - can intermingle plain text with its escape sequences. - &postscript; cannot directly print plain text, and that - is the kind of printer language for which we must make - special accommodations. - - - - Checking a Parallel Printer - - This section tells you how to check if &os; can - communicate with a printer connected to a parallelprintersparallel - port. - - To test a printer on a parallel - port: - - - - Become root with - &man.su.1;. - - - - Send data to the printer. - - - - If the printer can print plain text, then use - &man.lptest.1;. Type: - - &prompt.root; lptest > /dev/lptN - - Where N is the - number of the parallel port, starting from - zero. - - - - If the printer understands &postscript; or - other printer language, then send a small program - to the printer. Type: - - &prompt.root; cat > /dev/lptN - - Then, line by line, type the program - carefully as you cannot edit - a line once you have pressed - RETURN or - ENTER. When you have finished - entering the program, press - CONTROL+D, or whatever your - end of file key is. - - Alternatively, you can put the program in a - file and type: - - &prompt.root; cat file > /dev/lptN - - Where file is the - name of the file containing the program you want - to send to the printer. - - - - - - You should see something print. Do not worry if the - text does not look right; we will fix such things - later. - - - - Checking a Serial Printer - - - printers - serial - - This section tells you how to check if &os; can - communicate with a printer on a serial port. - - To test a printer on a serial - port: - - - - Become root with - &man.su.1;. - - - - Edit the file /etc/remote. - Add the following entry: - - printer:dv=/dev/port:br#bps-rate:pa=parity - - bits-per-second - serial port - parity - Where port is the - device entry for the serial port - (ttyu0, ttyu1, - etc.), bps-rate is the - bits-per-second rate at which the printer - communicates, and parity - is the parity required by the printer (either - even, odd, - none, or - zero). - - Here is a sample entry for a printer connected via - a serial line to the third serial port at - 19200 bps with no parity: - - printer:dv=/dev/ttyu2:br#19200:pa=none - - - - Connect to the printer with &man.tip.1;. - Type: - - &prompt.root; tip printer - - If this step does not work, edit the file - /etc/remote again and try using - /dev/cuaaN - instead of - /dev/ttyuN. - - - - Send data to the printer. - - - - If the printer can print plain text, then use - &man.lptest.1;. Type: - - &prompt.user; $lptest - - - - If the printer understands &postscript; or - other printer language, then send a small program - to the printer. Type the program, line by line, - very carefully as backspacing - or other editing keys may be significant to the - printer. You may also need to type a special - end-of-file key for the printer so it knows it - received the whole program. For &postscript; - printers, press - CONTROL+D. - - Alternatively, you can put the program in a - file and type: - - &prompt.user; >file - - Where file is the - name of the file containing the program. After - &man.tip.1; sends the file, press any required - end-of-file key. - - - - - - You should see something print. Do not worry if the - text does not look right; we will fix that later. - - - - - Enabling the Spooler: the - <filename>/etc/printcap</filename> File - - At this point, your printer should be hooked up, your - kernel configured to communicate with it (if necessary), - and you have been able to send some simple data to the - printer. Now, we are ready to configure - LPD to control access to your - printer. - - You configure LPD by editing - the file /etc/printcap. The - LPD spooling system reads this - file each time the spooler is used, so updates to the - file take immediate effect. - - - printers - capabilities - - The format of the &man.printcap.5; file is - straightforward. Use your favorite text editor to make - changes to /etc/printcap. The format - is identical to other capability files like - /usr/share/misc/termcap and - /etc/remote. For complete information - about the format, see the &man.cgetent.3;. - - The simple spooler configuration consists of the - following steps: - - - - Pick a name (and a few convenient aliases) for the - printer, and put them in the - /etc/printcap file; see the - Naming the - Printer section for more information on - naming. - - - - Turn off header pagesheader pages (which are on by default) by - inserting the sh capability; see the - Suppressing - Header Pages section for more - information. - - - - Make a spooling directory, and specify its location - with the sd capability; see the Making the Spooling - Directory section for more information. - - - - Set the /dev - entry to use for the printer, and note it in - /etc/printcap with the - lp capability; see the Identifying the Printer - Device for more information. Also, if the - printer is on a serial port, set up the communication - parameters with the ms# capability - which is discussed in the Configuring Spooler - Communications Parameters section. - - - - Install a plain text input filter; see the Installing the Text - Filter section for details. - - - - Test the setup by printing something with the - &man.lpr.1; command. More details are available in the - Trying It Out and - Troubleshooting - sections. - - - - - Language-based printers, such as &postscript; - printers, cannot directly print plain text. The simple - setup outlined above and described in the following - sections assumes that if you are installing such a printer - you will print only files that the printer can - understand. - - - Users often expect that they can print plain text to - any of the printers installed on your system. Programs - that interface to LPD to do their - printing usually make the same assumption. If you are - installing such a printer and want to be able to print jobs - in the printer language and print plain - text jobs, you are strongly urged to add an additional step - to the simple setup outlined above: install an automatic - plain-text-to-&postscript; (or other printer language) - conversion program. The section entitled Accommodating - Plain Text Jobs on &postscript; Printers tells how - to do this. - - - Naming the Printer - - The first (easy) step is to pick a name for your - printer. It really does not matter whether you choose - functional or whimsical names since you can also provide - a number of aliases for the printer. - - At least one of the printers specified in the - /etc/printcap should have the alias - lp. This is the default printer's - name. If users do not have the PRINTER - environment variable nor specify a printer name on the - command line of any of the LPD - commands, then lp will be the default - printer they get to use. - - Also, it is common practice to make the last alias - for a printer be a full description of the printer, - including make and model. - - Once you have picked a name and some common aliases, - put them in the /etc/printcap file. - The name of the printer should start in the leftmost - column. Separate each alias with a vertical bar and put - a colon after the last alias. - - In the following example, we start with a skeletal - /etc/printcap that defines two - printers (a Diablo 630 line printer and a Panasonic - KX-P4455 &postscript; laser printer): - - # -# /etc/printcap for host rose -# -rattan|line|diablo|lp|Diablo 630 Line Printer: - -bamboo|ps|PS|S|panasonic|Panasonic KX-P4455 PostScript v51.4: - - In this example, the first printer is named - rattan and has as aliases - line, diablo, - lp, and Diablo 630 Line - Printer. Since it has the alias - lp, it is also the default printer. - The second is named bamboo, and has - as aliases ps, PS, - S, panasonic, and - Panasonic KX-P4455 PostScript - v51.4. - - - - Suppressing Header Pages - - - printing - header pages - - - The LPD spooling system - will by default print a header page - for each job. The header page contains the user name who - requested the job, the host from which the job came, and - the name of the job, in nice large letters. - Unfortunately, all this extra text gets in the way of - debugging the simple printer setup, so we will suppress - header pages. - - To suppress header pages, add the - sh capability to the entry for the - printer in /etc/printcap. Here is - an example /etc/printcap with - sh added: - - # -# /etc/printcap for host rose - no header pages anywhere -# -rattan|line|diablo|lp|Diablo 630 Line Printer:\ - :sh: - -bamboo|ps|PS|S|panasonic|Panasonic KX-P4455 PostScript v51.4:\ - :sh: - - Note how we used the correct format: the first line - starts in the leftmost column, and subsequent lines are - indented. Every line in an entry except the last ends - in a backslash character. - - - - Making the Spooling Directory - - printer spool - print jobs - - The next step in the simple spooler setup is to make - a spooling directory, a directory - where print jobs reside until they are printed, and where - a number of other spooler support files live. - - Because of the variable nature of spooling - directories, it is customary to put these directories - under /var/spool. - It is not necessary to backup the contents of spooling - directories, either. Recreating them is as simple as - running &man.mkdir.1;. - - It is also customary to make the directory with a name - that is identical to the name of the printer, as shown - below: - - &prompt.root; mkdir /var/spool/printer-name - - However, if you have a lot of printers on your - network, you might want to put the spooling directories - under a single directory that you reserve just for - printing with LPD. We - will do this for our two example printers - rattan and - bamboo: - - &prompt.root; mkdir /var/spool/lpd -&prompt.root; mkdir /var/spool/lpd/rattan -&prompt.root; mkdir /var/spool/lpd/bamboo - - - If you are concerned about the privacy of jobs that - users print, you might want to protect the spooling - directory so it is not publicly accessible. Spooling - directories should be owned and be readable, writable, - and searchable by user daemon and - group daemon, and no one else. - We will do this for our example printers: - - &prompt.root; chown daemon:daemon /var/spool/lpd/rattan -&prompt.root; chown daemon:daemon /var/spool/lpd/bamboo -&prompt.root; chmod 770 /var/spool/lpd/rattan -&prompt.root; chmod 770 /var/spool/lpd/bamboo - - - Finally, you need to tell - LPD about these directories - using the /etc/printcap file. You - specify the pathname of the spooling directory with the - sd capability: - - # -# /etc/printcap for host rose - added spooling directories -# -rattan|line|diablo|lp|Diablo 630 Line Printer:\ - :sh:sd=/var/spool/lpd/rattan: - -bamboo|ps|PS|S|panasonic|Panasonic KX-P4455 PostScript v51.4:\ - :sh:sd=/var/spool/lpd/bamboo: - - Note that the name of the printer starts in the first - column but all other entries describing the printer should - be indented and each line end escaped with a - backslash. - - If you do not specify a spooling directory with - sd, the spooling system will use - /var/spool/lpd as - a default. - - - - Identifying the Printer Device - - In the Hardware - Setup section, we identified the port and the - relevant /dev - directory entry that &os; will use to communicate with - the printer. Now, we tell LPD - that information. When the spooling system has a job to - print, it will open the specified device on behalf of the - filter program (which is responsible for passing data to - the printer). - - List the /dev - entry pathname in the /etc/printcap - file using the lp capability. - - In our running example, let us assume that - rattan is on the first parallel port, - and bamboo is on a sixth serial port; - here are the additions to - /etc/printcap: - - # -# /etc/printcap for host rose - identified what devices to use -# -rattan|line|diablo|lp|Diablo 630 Line Printer:\ - :sh:sd=/var/spool/lpd/rattan:\ - :lp=/dev/lpt0: - -bamboo|ps|PS|S|panasonic|Panasonic KX-P4455 PostScript v51.4:\ - :sh:sd=/var/spool/lpd/bamboo:\ - :lp=/dev/ttyu5: - - If you do not specify the lp - capability for a printer in your - /etc/printcap file, - LPD uses - /dev/lp as a - default. /dev/lp - currently does not exist in &os;. - - If the printer you are installing is connected to a - parallel port, skip to the section entitled, Installing the Text - Filter. Otherwise, be sure to follow the - instructions in the next section. - - - - Configuring Spooler Communication Parameters - - - printers - serial - - - For printers on serial ports, - LPD can set up the bps rate, - parity, and other serial communication parameters on - behalf of the filter program that sends data to the - printer. This is advantageous since: - - - - It lets you try different communication parameters - by simply editing the - /etc/printcap file; you do not - have to recompile the filter program. - - - - It enables the spooling system to use the same - filter program for multiple printers which may have - different serial communication settings. - - - - The following /etc/printcap - capabilities control serial communication parameters of - the device listed in the lp - capability: - - - - br#bps-rate - - - Sets the communications speed of the device to - bps-rate, where - bps-rate can be 50, 75, - 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, - 4800, 9600, 19200, 38400, 57600, or 115200 - bits-per-second. - - - - - ms#stty-mode - - - Sets the options for the terminal device after - opening the device. &man.stty.1; explains the - available options. - - - - - When LPD opens the device - specified by the lp capability, it sets - the characteristics of the device to those specified with - the ms# capability. Of particular - interest will be the parenb, - parodd, cs5, - cs6, cs7, - cs8, cstopb, - crtscts, and ixon - modes, which are explained in the &man.stty.1; - manual page. - - Let us add to our example printer on the sixth serial - port. We will set the bps rate to 38400. For the mode, - we will set no parity with -parenb, - 8-bit characters with cs8, - no modem control with clocal and - hardware flow control with - crtscts: - - bamboo|ps|PS|S|panasonic|Panasonic KX-P4455 PostScript v51.4:\ - :sh:sd=/var/spool/lpd/bamboo:\ - :lp=/dev/ttyu5:ms#-parenb cs8 clocal crtscts: - - - - Installing the Text Filter - - - printing - filters - - - We are now ready to tell - LPD what text filter to use - to send jobs to the printer. A text - filter, also known as an input - filter, is a program that - LPD runs when it has a job to - print. When LPD runs the text - filter for a printer, it sets the filter's standard input - to the job to print, and its standard output to the - printer device specified with the lp - capability. The filter is expected to read the job from - standard input, perform any necessary translation for the - printer, and write the results to standard output, which - will get printed. For more information on the text - filter, see the Filters - section. - - For our simple printer setup, the text filter can be a - small shell script that just executes - /bin/cat to send the job to the - printer. &os; comes with another filter called - lpf that handles backspacing and - underlining for printers that might not deal with such - character streams well. And, of course, you can use any - other filter program you want. The filter - lpf is described in detail in section - entitled lpf: a - Text Filter. - - First, let us make the shell script - /usr/local/libexec/if-simple be a - simple text filter. Put the following text into that - file with your favorite text editor: - - #!/bin/sh -# -# if-simple - Simple text input filter for lpd -# Installed in /usr/local/libexec/if-simple -# -# Simply copies stdin to stdout. Ignores all filter arguments. - -/bin/cat && exit 0 -exit 2 - - Make the file executable: - - &prompt.root; chmod 555 /usr/local/libexec/if-simple - - And then tell LPD to use it by specifying it with the - if capability in - /etc/printcap. We will add it to - the two printers we have so far in the example - /etc/printcap: - - # -# /etc/printcap for host rose - added text filter -# -rattan|line|diablo|lp|Diablo 630 Line Printer:\ - :sh:sd=/var/spool/lpd/rattan:\ - :lp=/dev/lpt0:\ - :if=/usr/local/libexec/if-simple: - -bamboo|ps|PS|S|panasonic|Panasonic KX-P4455 PostScript v51.4:\ - :sh:sd=/var/spool/lpd/bamboo:\ - :lp=/dev/ttyu5:ms#-parenb cs8 clocal crtscts:\ - :if=/usr/local/libexec/if-simple: - - - A copy of the if-simple script - can be found in the /usr/share/examples/printing - directory. - - - - - Turn on <application>LPD</application> - - &man.lpd.8; is run from /etc/rc, - controlled by the lpd_enable variable. - This variable defaults to NO. If you - have not done so already, add the line: - - lpd_enable="YES" - - to /etc/rc.conf, and then either - restart your machine, or just run &man.lpd.8;. - - &prompt.root; lpd - - - - Trying It Out - - You have reached the end of the simple - LPD setup. - Unfortunately, congratulations are not quite yet in order, - since we still have to test the setup and correct any - problems. To test the setup, try printing something. To - print with the LPD system, you - use the command &man.lpr.1;, - which submits a job for printing. - - You can combine &man.lpr.1; with the &man.lptest.1; - program, introduced in section Checking Printer - Communications to generate some test text. - - To test the simple - LPD setup: - - Type: - - &prompt.root; lptest 20 5 | lpr -Pprinter-name - - Where printer-name is a the - name of a printer (or an alias) specified in - /etc/printcap. To test the default - printer, type &man.lpr.1; without any - argument. Again, if you are testing a printer that - expects &postscript;, send a &postscript; program in that - language instead of using &man.lptest.1;. You can do so - by putting the program in a file and typing lpr - file. - - For a &postscript; printer, you should get the results - of the program. If you are using &man.lptest.1;, then - your results should look like the following: - - !"#$%&'()*+,-./01234 -"#$%&'()*+,-./012345 -#$%&'()*+,-./0123456 -$%&'()*+,-./01234567 -%&'()*+,-./012345678 - - To further test the printer, try downloading larger - programs (for language-based printers) or running - &man.lptest.1; with different arguments. For example, - lptest 80 60 will produce 60 lines of - 80 characters each. - - If the printer did not work, see the Troubleshooting - section. - - + + + + &postscript; + + + &postscript; is almost the opposite of + ASCII. Rather than simple text, a + &postscript; program is a set of instructions that draw + the final document. Different fonts and graphics can be + used. However, this power comes at a price. The program + that draws the page must be written. Usually this program + is generated by application software, so the process is + invisible to the user. + + Inexpensive printers sometimes leave out &postscript; + compatibility as a cost-saving measure. + + + + + PCL (Printer Command Language) + + + PCL is an extension of + ASCII, adding escape sequences for + formatting, font selection, and printing graphics. Many + printers provide PCL5 support. Some + support the newer PCL6 or + PCLXL. These later versions are + supersets of PCL5 and can provide + faster printing. + + + + + Host-Based + + + Manufacturers can reduce the cost of a printer by + giving it a simple processor and very little memory. + These printers are not capable of printing plain text. + Instead, bitmaps of text and graphics are drawn by a + driver on the host computer and then sent to the printer. + These are called host-based + printers. + + Communication between the driver and a host-based + printer is often through proprietary or undocumented + protocols, making them functional only on the most common + operating systems. + + + + + + Converting &postscript; to Other + <acronym>PDL</acronym>s + + Many applications from the Ports Collection and &os; + utilities produce &postscript; output. This table shows + the utilities available to convert that into other common + PDLs: + + + Output <acronym>PDL</acronym>s + + + + + Output + PDL + Generated By + Notes + + + + + + PCL or + PCL5 + print/ghostscript9 + -sDEVICE=ljet4 for monochrome, + -sDEVICE=cljet5 for color + + + + PCLXL or + PCL6 + print/ghostscript9 + -sDEVICE=pxlmono for + monochrome, -sDEVICE=pxlcolor for + color + + + + ESC/P2 + print/ghostscript9 + -sDEVICE=uniprint + + + + XQX + print/foo2zjs + + + + +
+ + + + Summary + + For the easiest printing, choose a printer that supports + &postscript;. Printers that support PCL + are the next preferred. With + print/ghostscript, these + printers can be used as if they understood &postscript; + natively. Printers that support &postscript; or + PCL directly almost always support direct + printing of plain ASCII text files + also. + + Line-based printers like typical inkjets usually do not + support &postscript; or PCL. They often + can print plain ASCII text files. + print/ghostscript supports the + PDLs used by some of these printers. + However, printing an entire graphic-based page on these + printers is often very slow due to the large amount of data to + be transferred and printed. + + Host-based printers are often more difficult to set up. + Some cannot be used at all because of proprietary + PDLs. Avoid these printers when + possible. + + Descriptions of many PDLs can be found + at . + The particular PDL used by various models + of printers can be found at . - - Advanced Printer Setup + + Direct Printing - This section describes filters for printing specially - formatted files, header pages, printing across networks, and - restricting and accounting for printer usage. + For occasional printing, files can be sent directly to a + printer device without any setup. For example, a file called + sample.txt can be sent to a + USB printer: - + &prompt.root; cp sample.txt /dev/unlpt0 + + Direct printing to network printers depends on the + abilities of the printer, but most accept print jobs on port + 9100, and &man.nc.1; can be used with them. To print the + same file to a printer with the DNS + hostname of netlaser: + + &prompt.root; nc netlaser 9100 < sample.txt + + + + <acronym>LPD</acronym> (Line Printer Daemon) + + Printing a file in the background is called + spooling. A spooler allows the user to + continue with other programs on the computer without waiting for + the printer to slowly complete the print job. + + &os; includes a spooler called &man.lpd.8;. Print jobs are + submitted with &man.lpr.1;. + + + Initial Setup + + A directory for storing print jobs is created, ownership + is set, and the permissions are set to prevent other users + from viewing the contents of those files: + + &prompt.root; mkdir -p /var/spool/lpd/lp +&prompt.root; chown daemon:daemon /var/spool/lpd/lp +&prompt.root; chmod 770 /var/spool/lpd/lp + + Printers are defined in + /etc/printcap. An entry for each printer + includes details like a name, the port where it is attached, + and various other settings. Create + /etc/printcap with these contents: + + lp:\ + :lp=/dev/unlpt0:\ + :sh:\ + :mx#0:\ + :sd=/var/spool/lpd/lp:\ + :lf=/var/log/lpd-errs: + + + + The name of this printer. &man.lpr.1; sends print + jobs to the lp printer unless another + printer is specified with , so the + default printer should be named + lp. + + + + The device where the printer is connected. Replace + this line with the appropriate one for the connection type + shown here. + + + + + + Connection Type + Device Entry in + /etc/printcap + + + + + + USB + :lp=/dev/unlpt0:\ + + This is the + non-resetting + USB printer device. If + problems are experienced, use + ulpt0 instead, which resets + the USB port on each + use. + + + + Parallel + :lp=/dev/lpt0:\ + + + + Network + + For a printer supporting the + LPD protocol: + + :lp=:rm=network-printer-name:rp=raw:\ + + For printers supporting port 9100 + printing: + + :lp=9100@network-printer-name:\ + + For both types, replace + network-printer-name + with the DNS host name of the + network printer. + + + + Serial + :lp=/dev/cuau0:br=9600:pa=none:\ + + These values are for a typical serial + printer connected to a motherboard serial port. + The baud rate is 9600, and no parity is + used. + + + + + + + + Suppress the printing of a header page at the start of + a print job. + + + + Do not limit the maximum size of a print job. + + + + The path to the spooling directory for this printer. + Each printer uses its own spooling directory. + + + + The log file where errors on this printer will be + reported. + + + + After creating /etc/printcap, use + &man.chkprintcap.8; to test it for errors: + + &prompt.root; chkprintcap + + Fix any reported problems before continuing. + + Enable &man.lpd.8; in + /etc/rc.conf: + + lpd_enable="YES" + + Start the service: + + &prompt.root; service lpd start + + + + Printing with &man.lpr.1; + + Documents are sent to the printer with + lpr. A file to be printed can be named on + the command line or piped into lpr. These + two commands are equivalent, sending the contents of + doc.txt to the default printer: + + &prompt.user; lpr doc.txt +&prompt.user; cat doc.txt | lpr + + Printers can be selected with . To + print to a printer called + laser: + + &prompt.user; lpr -Plaser doc.txt + + + Filters - - printing - filters - + The examples shown so far have sent the contents of a text + file directly to the printer. As long as the printer + understands the content of those files, output will be printed + correctly. - Although LPD handles network - protocols, queuing, access control, and other aspects of - printing, most of the real work happens - in the filters. Filters are programs - that communicate with the printer and handle its device - dependencies and special requirements. In the simple printer - setup, we installed a plain text filter—an extremely - simple one that should work with most printers (section Installing the Text - Filter). + Some printers are not capable of printing plain text, and + the input file might not even be plain text. - However, in order to take advantage of format conversion, - printer accounting, specific printer quirks, and so on, you - should understand how filters work. It will ultimately be - the filter's responsibility to handle these aspects. And the - bad news is that most of the time you - have to provide filters yourself. The good news is that many - are generally available; when they are not, they are usually - easy to write. + Filters allow files to be + translated or processed. The typical use is to translate one + type of input, like plain text, into a form that the printer + can understand, like &postscript; or PCL. + Filters can also be used to provide additional features, like + adding page numbers or highlighting source code to make it + easier to read. - Also, &os; comes with one, - /usr/libexec/lpr/lpf, that works with - many printers that can print plain text. (It handles - backspacing and tabs in the file, and does accounting, but - that is about all it does.) There are also several filters - and filter components in the &os; Ports Collection. + The filters discussed here are + input filters or + text filters. These filters convert the + incoming file into different forms. Use &man.su.1; to become + root before + creating the files. - Here is what you will find in this section: + Filters are specified in + /etc/printcap with the + if= identifier. To use + /usr/local/libexec/lf2crlf as a filter, + modify /etc/printcap like this: - - - Section How - Filters Work, tries to give an overview of a - filter's role in the printing process. You should read - this section to get an understanding of what is happening - under the hood when - LPD uses filters. This - knowledge could help you anticipate and debug problems - you might encounter as you install more and more filters - for each of your printers. - + lp:\ + :lp=/dev/unlpt0:\ + :sh:\ + :mx#0:\ + :sd=/var/spool/lpd/lp:\ + :if=/usr/local/libexec/lf2crlf:\ + :lf=/var/log/lpd-errs: - - LPD expects every printer - to be able to print plain text by default. This presents - a problem for &postscript; printers (or other - language-based printers) which cannot directly print - plain text. Section Accommodating - Plain Text Jobs on &postscript; Printers tells - you what you should do to overcome this problem. You - should read this section if you have a &postscript; - printer. - + + + if= identifies the + input filter that will be used on + incoming text. + + - - &postscript; is a popular output format for many - programs. Some people even write &postscript; code - directly. Unfortunately, &postscript; printers are - expensive. Section Simulating &postscript; - on Non &postscript; Printers tells how you can - further modify a printer's text filter to accept and print - &postscript; data on a non - &postscript; printer. You should read this - section if you do not have a &postscript; printer. - + + The backslash line continuation + characters at the end of the lines in + printcap entries reveal that an entry + for a printer is really just one long line with entries + delimited by colon characters. An earlier example can be + rewritten as a single less-readable line: - - Section Conversion - Filters tells about a way you can automate the - conversion of specific file formats, such as graphic or - typesetting data, into formats your printer can - understand. After reading this section, you should be - able to set up your printers such that users can type - lpr -t to print troff - data, or lpr -d to - print &tex; DVI data, or lpr - -v to print raster image - data, and so forth. The reading of this section is - recommended. - + lp:lp=/dev/unlpt0:sh:mx#0:sd=/var/spool/lpd/lp:if=/usr/local/libexec/lf2crlf:lf=/var/log/lpd-errs: + - - Section Output - Filters tells all about a not often used feature - of LPD: output filters. Unless - you are printing header pages (see Header - Pages), you can probably skip that section - altogether. - + + Preventing Stairstepping on Plain Text Printers - - Section lpf: - a Text Filter describes lpf, - a fairly complete if simple text filter for line - printers (and laser printers that act like line - printers) that comes with &os;. If you need a quick - way to get printer accounting working for plain text, - or if you have a printer which emits smoke when it sees - backspace characters, you should definitely consider - lpf. - - + Typical &os; text files contain only a single line feed + character at the end of each line. These lines will + stairstep on a standard printer: - - A copy of the various scripts described below can be - found in the /usr/share/examples/printing - directory. - + A printed file looks + like the steps of a staircase + scattered by the wind - - How Filters Work + A filter can convert the newline characters into + carriage returns and newlines. The carriage returns make + the printer return to the left after each line. Create + /usr/local/libexec/lf2crlf with these + contents: - As mentioned before, a filter is an executable program - started by LPD to handle the - device-dependent part of communicating with the - printer. + #!/bin/sh +CR=`/usr/bin/printf "\r"` +/usr/bin/sed -e "s/$/${CR}/g" - When LPD wants to print a - file in a job, it starts a filter program. It sets the - filter's standard input to the file to print, its standard - output to the printer, and its standard error to the error - logging file (specified in the lf - capability in /etc/printcap, or - /dev/console by - default). + Set the permissions and make it executable: - - troff - - Which filter LPD starts and - the filter's arguments depend on what is listed in the - /etc/printcap file and what arguments - the user specified for the job on the &man.lpr.1; command - line. For example, if the user typed - lpr -t, - LPD would start the troff filter, - listed in the tf capability for the - destination printer. If the user wanted to print plain - text, it would start the if filter (this - is mostly true: see Output Filters for - details). + &prompt.root; chmod 555 /usr/local/libexec/lf2crlf - There are three kinds of filters you can specify in - /etc/printcap: + Modify /etc/printcap to use the + new filter: - - - The text filter, confusingly - called the input filter in - LPD documentation, handles - regular text printing. Think of it as the default - filter. LPD expects every - printer to be able to print plain text by default, - and it is the text filter's job to make sure backspaces, - tabs, or other special characters do not confuse the - printer. If you are in an environment where you have - to account for printer usage, the text filter must also - account for pages printed, usually by counting the - number of lines printed and comparing that to the number - of lines per page the printer supports. The text filter - is started with the following argument list: + :if=/usr/local/libexec/lf2crlf:\ - - filter-name - -c - -w - width - -l - length - -i - indent - -n - login - -h - host - acct-file - - - where - - - - - - - appears if the job is submitted with - lpr -l - - - - - width - - - is the value from the pw - (page width) capability specified in - /etc/printcap, default - 132 - - - - - length - - - is the value from the pl - (page length) capability, default 66 - - - - - indent - - - is the amount of the indentation from - lpr -i, - default 0 - - - - - login - - - is the account name of the user printing the - file - - - - - host - - - is the host name from which the job was - submitted - - - - - acct-file - - - is the name of the accounting file from the - af capability. - - - - - - - A conversion filterprintingfilters converts - a specific file format into one the printer can render - onto paper. For example, ditroff typesetting data - cannot be directly printed, but you can install a - conversion filter for ditroff files to convert the - ditroff data into a form the printer can digest and - print. Section Conversion - Filters tells all about them. Conversion - filters also need to do accounting, if you need printer - accounting. Conversion filters are started with the - following arguments: - - - filter-name - -x - pixel-width - -y - pixel-height - -n - login - -h - host - acct-file - - - where pixel-width is - the value from the px capability - (default 0) and pixel-height - is the value from the py capability - (default 0). - - - - The output filter is used - only if there is no text filter, or if header pages are - enabled. In our experience, output filters are rarely - used. Section Output Filters - describes them. There are only two arguments to an - output filter: - - - filter-name - -w - width - -l - length - - - which are identical to the text filters - and - arguments. - - - - Filters should also exit with the - following exit status: - - - - exit 0 - - - If the filter printed the file - successfully. - - - - - exit 1 - - - If the filter failed to print the file but wants - LPD to - try to print the file again. - LPD will restart a filter - if it exits with this status. - - - - - exit 2 - - - If the filter failed to print the file and does - not want LPD to try again. - LPD will throw out the - file. - - - - - The text filter that comes with the &os; release, - /usr/libexec/lpr/lpf, takes advantage - of the page width and length arguments to determine when - to send a form feed and how to account for printer usage. - It uses the login, host, and accounting file arguments to - make the accounting entries. - - If you are shopping for filters, see if they are - LPD-compatible. If they are, they must support the argument - lists described above. If you plan on writing filters for - general use, then have them support the same argument lists - and exit codes. + Test the filter by printing the same plain text file. + The carriage returns will cause each line to start at the + left side of the page. - - Accommodating Plain Text Jobs on &postscript; - Printers + + Fancy Plain Text on &postscript; Printers with + <package>print/enscript</package> - print jobs + GNU + Enscript converts plain text + files into nicely-formatted &postscript; for printing on + &postscript; printers. It adds page numbers, wraps long + lines, and provides numerous other features to make printed + text files easier to read. Depending on the local paper + size, install either + print/enscript-letter or + print/enscript-a4 from the + Ports Collection. - If you are the only user of your computer and - &postscript; (or other language-based) printer, and you - promise to never send plain text to your printer and to - never use features of various programs that will want to - send plain text to your printer, then you do not need to - worry about this section at all. + Create /usr/local/libexec/enscript + with these contents: - But, if you would like to send both &postscript; and - plain text jobs to the printer, then you are urged to - augment your printer setup. To do so, we have the text - filter detect if the arriving job is plain text or - &postscript;. All &postscript; jobs must start with - %! (for other printer languages, see - your printer documentation). If those are the first two - characters in the job, we have &postscript;, and can pass - the rest of the job directly. If those are not the first - two characters in the file, then the filter will convert - the text into &postscript; and print the result. + #!/bin/sh +/usr/local/bin/enscript -o - - How do we do this? + Set the permissions and make it executable: - - printers - serial - - If you have got a serial printer, a great way to do it - is to install lprps. - lprps is a &postscript; printer filter - which performs two-way communication with the printer. It - updates the printer's status file with verbose information - from the printer, so users and administrators can see - exactly what the state of the printer is (such as - toner low or paper - jam). But more importantly, it includes a - program called psif which detects whether - the incoming job is plain text and calls - textps (another program that comes with - lprps) to convert it to &postscript;. - It then uses lprps to send the job to - the printer. + &prompt.root; chmod 555 /usr/local/libexec/enscript - lprps is part of the &os; Ports - Collection (see The Ports - Collection). You can install one of the both - print/lprps-a4 and - print/lprps-letter ports - according to the paper size used. After installing - lprps, just specify the pathname to the - psif program that is part of - lprps. If you installed - lprps from the Ports Collection, use - the following in the serial &postscript; printer's entry - in /etc/printcap: + Modify /etc/printcap to use the + new filter: - :if=/usr/local/libexec/psif: + :if=/usr/local/libexec/enscript:\ - The rw capability should be also - included in order to let LPD to - open the printer in the read-write mode. + Test the filter by printing a plain text file. + - If you have a parallel &postscript; printer (and - therefore cannot use two-way communication with the printer, - which lprps needs), you can use the - following shell script as the text filter: + + Printing &postscript; to + <acronym>PCL</acronym> Printers + + Many programs produce &postscript; documents. + However, inexpensive printers often only understand plain + text or PCL. This filter converts + &postscript; files to PCL before sending + them to the printer. + + Install the Ghostscript &postscript; interpreter, + print/ghostscript9, from the + Ports Collection. + + Create /usr/local/libexec/ps2pcl + with these contents: + + #!/bin/sh +/usr/local/bin/gs -dSAFER -dNOPAUSE -q -sDEVICE=ljet4 -sOutputFile=- - + + Set the permissions and make it executable: + + &prompt.root; chmod 555 /usr/local/libexec/ps2pcl + + &postscript; input sent to this script will be rendered + and converted to PCL before being sent on + to the printer. + + Modify /etc/printcap to use this + new input filter: + + :if=/usr/local/libexec/ps2pcl:\ + + Test the filter by sending a small &postscript; program + to it: + + &prompt.user; printf "%%\!PS \n /Helvetica findfont 18 scalefont setfont \ +72 432 moveto (PostScript printing successful.) show showpage \004" | lpr + + + + Smart Filters + + A filter that detects the type of input and + automatically converts it to the correct format for the + printer can be very convenient. The first two characters of + a &postscript; file are usually %!. A + filter can detect those two characters. &postscript; files + can be sent on to a &postscript; printer unchanged. Text + files can be converted to &postscript; with + Enscript as shown earlier. + Create /usr/local/libexec/psif with + these contents: #!/bin/sh # # psif - Print PostScript or plain text on a PostScript printer -# Script version; NOT the version that comes with lprps -# Installed in /usr/local/libexec/psif -# - -IFS="" read -r first_line -first_two_chars=`expr "$first_line" : '\(..\)'` - -if [ "$first_two_chars" = "%!" ]; then - # - # PostScript job, print it. - # - echo "$first_line" && cat && printf "\004" && exit 0 - exit 2 -else - # - # Plain text, convert it, then print it. - # - ( echo "$first_line"; cat ) | /usr/local/bin/textps && printf "\004" && exit 0 - exit 2 -fi - - In the above script, textps is a - program we installed separately to convert plain text to - &postscript;. You can use any text-to-&postscript; program - you wish. The &os; Ports Collection (see The Ports Collection) includes a - full featured text-to-&postscript; program called - a2ps that you might want to - investigate. - - - - Simulating &postscript; on Non &postscript; - Printers - - - PostScript - emulating - - Ghostscript - - &postscript; is the de facto - standard for high quality typesetting and printing. - &postscript; is, however, an expensive - standard. Thankfully, Aladdin Enterprises has a free - &postscript; work-alike called - Ghostscript that runs with &os;. - Ghostscript can read most - &postscript; files and can render their pages onto a variety - of devices, including many brands of non-&postscript; - printers. By installing - Ghostscript and using a special - text filter for your printer, you can make your non - &postscript; printer act like a real &postscript; - printer. - - Ghostscript is in the &os; - Ports Collection, many versions are available, the most - commonly used version is print/ghostscript-gpl. - - To simulate &postscript;, we have the text filter detect - if it is printing a &postscript; file. If it is not, then - the filter will pass the file directly to the printer; - otherwise, it will use - Ghostscript to first convert the - file into a format the printer will understand. - - Here is an example: the following script is a text - filter for Hewlett Packard DeskJet 500 printers. For other - printers, substitute the argument - to the gs - (Ghostscript) command. (Type - gs -h to get a list of - devices the current installation of - Ghostscript supports.) - - #!/bin/sh -# -# ifhp - Print Ghostscript-simulated PostScript on a DeskJet 500 -# Installed in /usr/local/libexec/ifhp - -# -# Treat LF as CR+LF (to avoid the "staircase effect" on HP/PCL -# printers): -# -printf "\033&k2G" || exit 2 - -# -# Read first two characters of the file # IFS="" read -r first_line first_two_chars=`expr "$first_line" : '\(..\)'` -if [ "$first_two_chars" = "%!" ]; then - # - # It is PostScript; use Ghostscript to scan-convert and print it. - # - /usr/local/bin/gs -dSAFER -dNOPAUSE -q -sDEVICE=djet500 \ - -sOutputFile=- - && exit 0 -else - # - # Plain text or HP/PCL, so just print it directly; print a form feed - # at the end to eject the last page. - # - echo "$first_line" && cat && printf "\033&l0H" && -exit 0 -fi - -exit 2 - - Finally, you need to notify - LPD of the filter via the - if capability: - - :if=/usr/local/libexec/ifhp: - - That is it. You can type - lpr - plain.text - and - lpr - whatever.ps - and both should print successfully. - - - - Conversion Filters - - After completing the simple setup described in Simple Printer Setup, - the first thing you will probably want to do is install - conversion filters for your favorite file formats (besides - plain ASCII text). - - - Why Install Conversion Filters? - - - &tex; - printing DVI files - - - Conversion filters make printing various kinds of - files easy. As an example, suppose we do a lot of work - with the &tex; typesetting system, and we have a - &postscript; printer. Every time we generate a DVI file - from &tex;, we cannot print it directly until we convert - the DVI file into &postscript;. The command sequence - goes like this: - - &prompt.user; dvips seaweed-analysis.dvi -&prompt.user; lpr seaweed-analysis.ps - - By installing a conversion filter for DVI files, we - can skip the hand conversion step each time by having - LPD do it for us. Now, each - time we get a DVI file, we are just one step away from - printing it: - - &prompt.user; lpr -d seaweed-analysis.dvi - - We got LPD to do the DVI - file conversion for us by specifying the - option. Section Formatting and - Conversion Options lists the conversion - options. - - For each of the conversion options you want a printer - to support, install a conversion - filter and specify its pathname in - /etc/printcap. A conversion filter - is like the text filter for the simple printer setup (see - section Installing - the Text Filter) except that instead of printing - plain text, the filter converts the file into a format - the printer can understand. - - - - Which Conversion Filters Should I Install? - - You should install the conversion filters you expect - to use. If you print a lot of DVI data, then a DVI - conversion filter is in order. If you have got plenty - of troff to print out, then you probably want a troff - filter. - - The following table summarizes the filters that - LPD works - with, their capability entries for the - /etc/printcap file, and how to - invoke them with the lpr - command: - - - - - - File type - /etc/printcap - capability - lpr option - - - - - - cifplot - cf - - - - - DVI - df - - - - - plot - gf - - - - - ditroff - nf - - - - - FORTRAN text - rf - - - - - troff - tf - - - - - raster - vf - - - - - plain text - if - none, , or - - - - - - - In our example, using - lpr -d means the - printer needs a df capability in its - entry in /etc/printcap. - - FORTRAN - Despite what others might contend, formats like - FORTRAN text and plot are probably obsolete. At your - site, you can give new meanings to these or any of the - formatting options just by installing custom filters. - For example, suppose you would like to directly print - Printerleaf files (files from the Interleaf desktop - publishing program), but will never print plot files. - You could install a Printerleaf conversion filter under - the gf capability and then educate your - users that lpr -g mean - print Printerleaf files. - - - - Installing Conversion Filters - - Since conversion filters are programs you install - outside of the base &os; installation, they should - probably go under /usr/local. The - directory /usr/local/libexec is a - popular location, since they are specialized programs - that only LPD will run; regular - users should not ever need to run them. - - To enable a conversion filter, specify its pathname - under the appropriate capability for the destination - printer in /etc/printcap. - - In our example, we will add the DVI conversion filter - to the entry for the printer named - bamboo. Here is the example - /etc/printcap file again, with - the new df capability for the printer - bamboo: - - # -# /etc/printcap for host rose - added df filter for bamboo -# -rattan|line|diablo|lp|Diablo 630 Line Printer:\ - :sh:sd=/var/spool/lpd/rattan:\ - :lp=/dev/lpt0:\ - :if=/usr/local/libexec/if-simple: - -bamboo|ps|PS|S|panasonic|Panasonic KX-P4455 PostScript v51.4:\ - :sh:sd=/var/spool/lpd/bamboo:\ - :lp=/dev/ttyu5:ms#-parenb cs8 clocal crtscts:rw:\ - :if=/usr/local/libexec/psif:\ - :df=/usr/local/libexec/psdf: - - The DVI filter is a shell script named - /usr/local/libexec/psdf. Here is - that script: - - #!/bin/sh -# -# psdf - DVI to PostScript printer filter -# Installed in /usr/local/libexec/psdf -# -# Invoked by lpd when user runs lpr -d -# -exec /usr/local/bin/dvips -f | /usr/local/libexec/lprps "$@" - - This script runs dvips in filter - mode (the argument) on standard input, - which is the job to print. It then starts the - &postscript; printer filter lprps - (see section Accommodating - Plain Text Jobs on &postscript; Printers) with - the arguments LPD passed to - this script. The lprps utility will - use those arguments to account for the pages - printed. - - - - More Conversion Filter Examples - - There is no fixed set of steps to install conversion - filters, some working examples are described in this - section. Use these as guidance to making your own - filters. Use them directly, if appropriate. - - This example script is a raster (well, GIF file, - actually) conversion filter for a Hewlett Packard LaserJet - III-Si printer: - - #!/bin/sh -# -# hpvf - Convert GIF files into HP/PCL, then print -# Installed in /usr/local/libexec/hpvf - -PATH=/usr/X11R6/bin:$PATH; export PATH -giftopnm | ppmtopgm | pgmtopbm | pbmtolj -resolution 300 \ - && exit 0 \ - || exit 2 - - It works by converting the GIF file into a portable - anymap, converting that into a portable graymap, - converting that into a portable bitmap, and converting - that into LaserJet/PCL-compatible data. - - Here is the /etc/printcap file - with an entry for a printer using the above filter: - - # -# /etc/printcap for host orchid -# -teak|hp|laserjet|Hewlett Packard LaserJet 3Si:\ - :lp=/dev/lpt0:sh:sd=/var/spool/lpd/teak:mx#0:\ - :if=/usr/local/libexec/hpif:\ - :vf=/usr/local/libexec/hpvf: - - The following script is a conversion filter for troff - data from the groff typesetting system for the - &postscript; printer named - bamboo: - - #!/bin/sh -# -# pstf - Convert groff's troff data into PS, then print. -# Installed in /usr/local/libexec/pstf -# -exec grops | /usr/local/libexec/lprps "$@" - - The above script makes use of lprps - again to handle the communication with the printer. If - the printer were on a parallel port, we would use this - script instead: - - #!/bin/sh -# -# pstf - Convert groff's troff data into PS, then print. -# Installed in /usr/local/libexec/pstf -# -exec grops - - That is it. Here is the entry we need to add to - /etc/printcap to enable the - filter: - - :tf=/usr/local/libexec/pstf: - - Here is an example that might make old hands at - FORTRAN blush. It is a FORTRAN-text filter for any - printer that can directly print plain text. We will - install it for the printer teak: - - #!/bin/sh -# -# hprf - FORTRAN text filter for LaserJet 3si: -# Installed in /usr/local/libexec/hprf -# - -printf "\033&k2G" && fpr && printf "\033&l0H" && - exit 0 -exit 2 - - And we will add this line to the - /etc/printcap for the printer - teak to enable this filter: - - :rf=/usr/local/libexec/hprf: - - Here is one final, somewhat complex example. We - will add a DVI filter to the LaserJet printer - teak introduced earlier. First, the - easy part: updating /etc/printcap - with the location of the DVI filter: - - :df=/usr/local/libexec/hpdf: - - Now, for the hard part: making the filter. For that, - we need a DVI-to-LaserJet/PCL conversion program. The - &os; Ports Collection (see The Ports - Collection) has one: print/dvi2xx. Installing this - port gives us the program we need, - dvilj2p, which converts DVI into - LaserJet IIp, LaserJet III, and LaserJet 2000 compatible - codes. - - The dvilj2p utility makes the - filter hpdf quite complex since - dvilj2p cannot read from standard - input. It wants to work with a filename. What is worse, - the filename has to end in .dvi so - using /dev/fd/0 - for standard input is problematic. We can get around that - problem by linking (symbolically) a temporary file name - (one that ends in .dvi) to - /dev/fd/0, thereby - forcing dvilj2p to read from standard - input. - - The only other fly in the ointment is the fact that - we cannot use /tmp - for the temporary link. Symbolic links are owned by user - and group bin. The filter runs as - user daemon. And the /tmp directory has the - sticky bit set. The filter can create the link, but it - will not be able clean up when done and remove it since - the link will belong to a different user. - - Instead, the filter will make the symbolic link in - the current working directory, which is the spooling - directory (specified by the sd - capability in /etc/printcap). This - is a perfect place for filters to do their work, - especially since there is (sometimes) more free disk space - in the spooling directory than under - /tmp. - - Here, finally, is the filter: - - #!/bin/sh -# -# hpdf - Print DVI data on HP/PCL printer -# Installed in /usr/local/libexec/hpdf - -PATH=/usr/local/bin:$PATH; export PATH - -# -# Define a function to clean up our temporary files. These exist -# in the current directory, which will be the spooling directory -# for the printer. -# -cleanup() { - rm -f hpdf$$.dvi -} - -# -# Define a function to handle fatal errors: print the given message -# and exit 2. Exiting with 2 tells LPD to do not try to reprint the -# job. -# -fatal() { - echo "$@" 1>&2 - cleanup +case "$first_two_chars" in +%!) + # %! : PostScript job, print it. + echo "$first_line" && cat && exit 0 exit 2 -} - -# -# If user removes the job, LPD will send SIGINT, so trap SIGINT -# (and a few other signals) to clean up after ourselves. -# -trap cleanup 1 2 15 - -# -# Make sure we are not colliding with any existing files. -# -cleanup - -# -# Link the DVI input file to standard input (the file to print). -# -ln -s /dev/fd/0 hpdf$$.dvi || fatal "Cannot symlink /dev/fd/0" - -# -# Make LF = CR+LF -# -printf "\033&k2G" || fatal "Cannot initialize printer" - -# -# Convert and print. Return value from dvilj2p does not seem to be -# reliable, so we ignore it. -# -dvilj2p -M1 -q -e- dfhp$$.dvi - -# -# Clean up and exit -# -cleanup -exit 0 - - - - Automated Conversion: an Alternative to Conversion - Filters - - All these conversion filters accomplish a lot for your - printing environment, but at the cost forcing the user - to specify (on the &man.lpr.1; command line) which one - to use. If your users are not particularly computer - literate, having to specify a filter option will become - annoying. What is worse, though, is that an incorrectly - specified filter option may run a filter on the wrong - type of file and cause your printer to spew out hundreds - of sheets of paper. - - Rather than install conversion filters at all, you - might want to try having the text filter (since it is the - default filter) detect the type of file it has been asked - to print and then automatically run the right conversion - filter. Tools such as file can be of - help here. Of course, it will be hard to determine the - differences between some file - types—and, of course, you can still provide - conversion filters just for them. - - apsfilter - - printing - filters - apsfilter - - The &os; Ports Collection has a text filter that - performs automatic conversion called - apsfilter (print/apsfilter). It can - detect plain text, &postscript;, DVI and almost any kind - of files, run the proper conversions, and print. - - - - - Output Filters - - The LPD spooling system - supports one other type of filter that we have not yet - explored: an output filter. An output filter is intended - for printing plain text only, like the text filter, but - with many simplifications. If you are using an output - filter but no text filter, then: - - - - LPD starts an output - filter once for the entire job instead of once for each - file in the job. - - - - LPD does not make any - provision to identify the start or the end of files - within the job for the output filter. - - - - LPD does not pass the - user's login or host to the filter, so it is not - intended to do accounting. In fact, it gets only two - arguments: - - - filter-name - -wwidth - -llength - - - Where width is from the - pw capability and - length is from the - pl capability for the printer in - question. - - - - Do not be seduced by an output filter's simplicity. - If you would like each file in a job to start on a different - page an output filter will not work. - Use a text filter (also known as an input filter); see - section Installing the - Text Filter. Furthermore, an output filter is - actually more complex in that it has - to examine the byte stream being sent to it for special - flag characters and must send signals to itself on behalf - of LPD. - - However, an output filter is - necessary if you want header pages and - need to send escape sequences or other initialization - strings to be able to print the header page. (But it is - also futile if you want to charge - header pages to the requesting user's account, since - LPD does not give any user or - host information to the output filter.) - - On a single printer, LPD - allows both an output filter and text or other filters. - In such cases, LPD will start - the output filter to print the header page (see section - Header - Pages) only. LPD then - expects the output filter to stop - itself by sending two bytes to the filter: - ASCII 031 followed by ASCII 001. When an output filter - sees these two bytes (031, 001), it should stop by sending - SIGSTOP to itself. When - LPD's done running other filters, - it will restart the output filter by sending - SIGCONT to it. - - If there is an output filter but no - text filter and LPD is working - on a plain text job, LPD uses - the output filter to do the job. As stated before, the - output filter will print each file of the job in sequence - with no intervening form feeds or other paper advancement, - and this is probably not what you want. - In almost all cases, you need a text filter. - - The program lpf, which we introduced - earlier as a text filter, can also run as an output filter. - If you need a quick-and-dirty output filter but do not want - to write the byte detection and signal sending code, try - lpf. You can also wrap - lpf in a shell script to handle any - initialization codes the printer might require. - - - - <command>lpf</command>: a Text Filter - - The program /usr/libexec/lpr/lpf - that comes with &os; binary distribution is a text filter - (input filter) that can indent output (job submitted with - lpr -i), allow literal - characters to pass (job submitted with - lpr -l), adjust the - printing position for backspaces and tabs in the job, and - account for pages printed. It can also act like an output - filter. - - The lpf filter is suitable for many - printing environments. And although it has no capability - to send initialization sequences to a printer, it is easy - to write a shell script to do the needed initialization - and then execute lpf. - - page accounting - - accounting - printer - - In order for lpf to do page - accounting correctly, it needs correct values filled in - for the pw and pl - capabilities in the /etc/printcap file. - It uses these values to determine how much text can fit on - a page and how many pages were in a user's job. For more - information on printer accounting, see Accounting for Printer - Usage. - - - - - Header Pages - - If you have lots of users, all of - them using various printers, then you probably want to - consider header pages as a necessary - evil. - - - banner pages - header pages - - header pages - Header pages, also known as banner - or burst pages identify to whom jobs - belong after they are printed. They are usually printed in - large, bold letters, perhaps with decorative borders, so that - in a stack of printouts they stand out from the real documents - that comprise users' jobs. They enable users to locate their - jobs quickly. The obvious drawback to a header page is that - it is yet one more sheet that has to be printed for every job, - their ephemeral usefulness lasting not more than a few - minutes, ultimately finding themselves in a recycling bin or - rubbish heap. (Note that header pages go with each job, not - each file in a job, so the paper waste might not be that - bad.) - - The LPD system can provide - header pages automatically for your printouts - if your printer can directly print - plain text. If you have a &postscript; printer, you will - need an external program to generate the header page; see - Header Pages - on &postscript; Printers. - - - Enabling Header Pages - - In the Simple Printer - Setup section, we turned off header pages by - specifying sh (meaning suppress - header) in the /etc/printcap - file. To enable header pages for a printer, just remove the - sh capability. - - Sounds too easy, right? - - You are right. You might have to - provide an output filter to send initialization strings to - the printer. Here is an example output filter for Hewlett - Packard PCL-compatible printers: - - #!/bin/sh -# -# hpof - Output filter for Hewlett Packard PCL-compatible printers -# Installed in /usr/local/libexec/hpof - -printf "\033&k2G" || exit 2 -exec /usr/libexec/lpr/lpf - - Specify the path to the output filter in the - of capability. See the Output Filters - section for more information. - - Here is an example /etc/printcap - file for the printer teak that we - introduced earlier; we enabled header pages and added the - above output filter: - - # -# /etc/printcap for host orchid -# -teak|hp|laserjet|Hewlett Packard LaserJet 3Si:\ - :lp=/dev/lpt0:sd=/var/spool/lpd/teak:mx#0:\ - :if=/usr/local/libexec/hpif:\ - :vf=/usr/local/libexec/hpvf:\ - :of=/usr/local/libexec/hpof: - - Now, when users print jobs to teak, - they get a header page with each job. If users want to - spend time searching for their printouts, they can suppress - header pages by submitting the job with lpr - -h; see the Header Page - Options section for more &man.lpr.1; - options. - - - LPD prints a form feed - character after the header page. If your printer uses - a different character or sequence of characters to eject - a page, specify them with the ff - capability in /etc/printcap. - - - - - Controlling Header Pages - - By enabling header pages, LPD - will produce a long header, a full - page of large letters identifying the user, host, and job. - Here is an example (kelly printed the - job named outline from host - rose): - - k ll ll - k l l - k l l - k k eeee l l y y - k k e e l l y y - k k eeeeee l l y y - kk k e l l y y - k k e e l l y yy - k k eeee lll lll yyy y - y - y y - yyyy - - - ll - t l i - t l - oooo u u ttttt l ii n nnn eeee - o o u u t l i nn n e e - o o u u t l i n n eeeeee - o o u u t l i n n e - o o u uu t t l i n n e e - oooo uuu u tt lll iii n n eeee - - - - - - - - - - r rrr oooo ssss eeee - rr r o o s s e e - r o o ss eeeeee - r o o ss e - r o o s s e e - r oooo ssss eeee - - - - - - - - Job: outline - Date: Sun Sep 17 11:04:58 1995 - - LPD appends a form feed after - this text so the job starts on a new page (unless you have - sf (suppress form feeds) in the - destination printer's entry in - /etc/printcap). - - If you prefer, LPD can make - a short header; specify - sb (short banner) in the - /etc/printcap file. The header page - will look like this: - - rose:kelly Job: outline Date: Sun Sep 17 11:07:51 1995 - - Also by default, LPD prints - the header page first, then the job. To reverse that, - specify hl (header last) in - /etc/printcap. - - - - Accounting for Header Pages - - Using LPD's built-in header - pages enforces a particular paradigm when it comes to - printer accounting: header pages must be free of - charge. - - Why? - - Because the output filter is the only external program - that will have control when the header page is printed that - could do accounting, and it is not provided with any - user or host information or an - accounting file, so it has no idea whom to charge for - printer use. It is also not enough to just increase - the page count by one by modifying the text - filter or any of the conversion filters (which do have user - and host information) since users can suppress header pages - with lpr -h. They could - still be charged for header pages they did not print. - Basically, lpr -h will - be the preferred option of environmentally-minded users, - but you cannot offer any incentive to use it. - - It is still not enough to have each - of the filters generate their own header pages (thereby - being able to charge for them). If users wanted the option - of suppressing the header pages with lpr - -h, they will still get them - and be charged for them since LPD - does not pass any knowledge of the - option to any of the filters. - - So, what are your options? - - You can: - - - - Accept LPD's paradigm - and make header pages free. - - - - Install an alternative to - LPD, such as - LPRng. Section Alternatives to - the Standard Spooler tells more about other - spooling software you can substitute for - LPD. - - - - Write a smart output filter. - Normally, an output filter is not meant to do anything - more than initialize a printer or do some simple - character conversion. It is suited for header pages - and plain text jobs (when there is no text (input) - filter). But, if there is a text filter for the plain - text jobs, then LPD will - start the output filter only for the header pages. - And the output filter can parse the header page text - that LPD generates to - determine what user and host to charge for the header - page. The only other problem with this method is that - the output filter still does not know what accounting - file to use (it is not passed the name of the file from - the af capability), but if you have - a well-known accounting file, you can hard-code that - into the output filter. To facilitate the parsing step, - use the sh (short header) capability - in /etc/printcap. Then again, all - that might be too much trouble, and users will certainly - appreciate the more generous system administrator who - makes header pages free. - - - - - - Header Pages on &postscript; Printers - - As described above, LPD can - generate a plain text header page suitable for many - printers. Of course, &postscript; cannot directly print - plain text, so the header page feature of - LPD is useless—or mostly - so. - - One obvious way to get header pages is to have every - conversion filter and the text filter generate the header - page. The filters should use the user and host arguments - to generate a suitable header page. The drawback of this - method is that users will always get a header page, even - if they submit jobs with lpr - -h. - - Let us explore this method. The following script takes - three arguments (user login name, host name, and job name) - and makes a simple &postscript; header page: - - #!/bin/sh -# -# make-ps-header - make a PostScript header page on stdout -# Installed in /usr/local/libexec/make-ps-header -# - -# -# These are PostScript units (72 to the inch). Modify for A4 or -# whatever size paper you are using: -# -page_width=612 -page_height=792 -border=72 - -# -# Check arguments -# -if [ $# -ne 3 ]; then - echo "Usage: `basename $0` <user> <host> <job>" 1>&2 - exit 1 -fi - -# -# Save these, mostly for readability in the PostScript, below. -# -user=$1 -host=$2 -job=$3 -date=`date` - -# -# Send the PostScript code to stdout. -# -exec cat <<EOF -%!PS - -% -% Make sure we do not interfere with user's job that will follow -% -save - -% -% Make a thick, unpleasant border around the edge of the paper. -% -$border $border moveto -$page_width $border 2 mul sub 0 rlineto -0 $page_height $border 2 mul sub rlineto -currentscreen 3 -1 roll pop 100 3 1 roll setscreen -$border 2 mul $page_width sub 0 rlineto closepath -0.8 setgray 10 setlinewidth stroke 0 setgray - -% -% Display user's login name, nice and large and prominent -% -/Helvetica-Bold findfont 64 scalefont setfont -$page_width ($user) stringwidth pop sub 2 div $page_height 200 sub moveto -($user) show - -% -% Now show the boring particulars -% -/Helvetica findfont 14 scalefont setfont -/y 200 def -[ (Job:) (Host:) (Date:) ] { -200 y moveto show /y y 18 sub def } -forall - -/Helvetica-Bold findfont 14 scalefont setfont -/y 200 def -[ ($job) ($host) ($date) ] { - 270 y moveto show /y y 18 sub def -} forall - -% -% That is it -% -restore -showpage -EOF - - Now, each of the conversion filters and the text filter - can call this script to first generate the header page, and - then print the user's job. Here is the DVI conversion - filter from earlier in this document, modified to make a - header page: - - #!/bin/sh -# -# psdf - DVI to PostScript printer filter -# Installed in /usr/local/libexec/psdf -# -# Invoked by lpd when user runs lpr -d -# - -orig_args="$@" - -fail() { - echo "$@" 1>&2 + ;; +*) + # otherwise, format with enscript + ( echo "$first_line"; cat ) | /usr/local/bin/enscript -o - && exit 0 exit 2 -} + ;; +esac -while getopts "x:y:n:h:" option; do - case $option in - x|y) ;; # Ignore - n) login=$OPTARG ;; - h) host=$OPTARG ;; - *) echo "LPD started `basename $0` wrong." 1>&2 - exit 2 - ;; - esac -done + Set the permissions and make it executable: -[ "$login" ] || fail "No login name" -[ "$host" ] || fail "No host name" + &prompt.root; chmod 555 /usr/local/libexec/psif -( /usr/local/libexec/make-ps-header $login $host "DVI File" - /usr/local/bin/dvips -f ) | eval /usr/local/libexec/lprps $orig_args + Modify /etc/printcap to use this + new input filter: - Notice how the filter has to parse the argument list in - order to determine the user and host name. The parsing for - the other conversion filters is identical. The text filter - takes a slightly different set of arguments, though (see - section How - Filters Work). + :if=/usr/local/libexec/psif:\ - As we have mentioned before, the above scheme, though - fairly simple, disables the suppress header - page option (the option) to - lpr. If users wanted to save a tree (or - a few pennies, if you charge for header pages), they would - not be able to do so, since every filter's going to print a - header page with every job. + Test the filter by printing &postscript; and plain text + files. + - To allow users to shut off header pages on a per-job - basis, you will need to use the trick introduced in section - Accounting - for Header Pages: write an output filter that parses - the LPD-generated header page and produces a &postscript; - version. If the user submits the job with - lpr -h, - then LPD will not generate a - header page, and neither will your output filter. - Otherwise, your output filter will read the text from - LPD and send the appropriate - header page &postscript; code to the printer. + + Other Smart Filters - If you have a &postscript; printer on a serial line, you - can make use of lprps, which comes with - an output filter, psof, which does the - above. Note that psof does not charge - for header pages. + Writing a filter that detects many different types of + input and formats them correctly is challenging. + print/apsfilter from the + Ports Collection is a smart magic filter that + detects dozens of file types and automatically converts them + to the PDL understood by the printer. + See for + more details. - - Networked Printing + + Multiple Queues - - printers - network - - network printing - &os; supports networked printing: sending jobs to remote - printers. Networked printing generally refers to two - different things: + The entries in /etc/printcap are + really definitions of queues. There can + be more than one queue for a single printer. When combined + with filters, multiple queues provide users more control over + how their jobs are printed. - - - Accessing a printer attached to a remote host. You - install a printer that has a conventional serial or - parallel interface on one host. Then, you set up - LPD to enable access to the - printer from other hosts on the network. Section Printers - Installed on Remote Hosts tells how to do - this. - + As an example, consider a networked &postscript; laser + printer in an office. Most users want to print plain text, + but a few advanced users want to be able to print &postscript; + files directly. Two entries can be created for the same + printer in /etc/printcap: - - Accessing a printer attached directly to a network. - The printer has a network interface in addition to (or in - place of) a more conventional serial or parallel - interface. Such a printer might work as follows: + textprinter:\ + :lp=9100@officelaser:\ + :sh:\ + :mx#0:\ + :sd=/var/spool/lpd/textprinter:\ + :if=/usr/local/libexec/enscript:\ + :lf=/var/log/lpd-errs: - - - It might understand the - LPD protocol and can even - queue jobs from remote hosts. In this case, it acts - just like a regular host running - LPD. Follow the same - procedure in section Printers - Installed on Remote Hosts to set up such a - printer. - +psprinter:\ + :lp=9100@officelaser:\ + :sh:\ + :mx#0:\ + :sd=/var/spool/lpd/psprinter:\ + :lf=/var/log/lpd-errs: - - It might support a data stream network connection. - In this case, you attach the printer to - one host on the network by making that host - responsible for spooling jobs and sending them to the - printer. Section Printers - with Networked Data Stream Interfaces gives - some suggestions on installing such printers. - - - - + Documents sent to textprinter will be + formatted by the + /usr/local/libexec/enscript filter shown + in an earlier example. Advanced users can print &postscript; + files on psprinter, where no filtering is + done. - - Printers Installed on Remote Hosts - - The LPD spooling system has - built-in support for sending jobs to other hosts also - running LPD (or are compatible - with LPD). This feature enables - you to install a printer on one host and make it accessible - from other hosts. It also works with printers that have - network interfaces that understand the - LPD protocol. - - To enable this kind of remote printing, first install a - printer on one host, the printer host, - using the simple printer setup described in the Simple Printer Setup - section. Do any advanced setup in Advanced Printer Setup - that you need. Make sure to test the printer and see if it - works with the features of LPD - you have enabled. Also ensure that the local - host has authorization to use the - LPD service in the - remote host (see Restricting - Jobs from Remote Hosts). - - - printers - network - - network printing - If you are using a printer with a network interface that - is compatible with LPD, then the - printer host in the discussion below is - the printer itself, and the printer - name is the name you configured for the - printer. See the documentation that accompanied your - printer and/or printer-network interface. - - - If you are using a Hewlett Packard Laserjet then the - printer name text will automatically - perform the LF to CRLF conversion for you, so you will not - require the hpif script. - - - Then, on the other hosts you want to have access to the - printer, make an entry in their - /etc/printcap files with the - following: - - - - Name the entry anything you want. For simplicity, - though, you probably want to use the same name and - aliases as on the printer host. - - - - Leave the lp capability blank, - explicitly (:lp=:). - - - - Make a spooling directory and specify its location - in the sd capability. - LPD will store jobs here - before they get sent to the printer host. - - - - Place the name of the printer host in the - rm capability. - - - - Place the printer name on the printer - host in the rp - capability. - - - - That is it. You do not need to list conversion filters, - page dimensions, or anything else in the - /etc/printcap file. - - Here is an example. The host rose has - two printers, bamboo and - rattan. We will enable users on the host - orchid to print to those printers. Here is - the /etc/printcap file for - orchid (back from section Enabling - Header Pages). It already had the entry for the - printer teak; we have added entries for - the two printers on the host rose: - - # -# /etc/printcap for host orchid - added (remote) printers on rose -# - -# -# teak is local; it is connected directly to orchid: -# -teak|hp|laserjet|Hewlett Packard LaserJet 3Si:\ - :lp=/dev/lpt0:sd=/var/spool/lpd/teak:mx#0:\ - :if=/usr/local/libexec/ifhp:\ - :vf=/usr/local/libexec/vfhp:\ - :of=/usr/local/libexec/ofhp: - -# -# rattan is connected to rose; send jobs for rattan to rose: -# -rattan|line|diablo|lp|Diablo 630 Line Printer:\ - :lp=:rm=rose:rp=rattan:sd=/var/spool/lpd/rattan: - -# -# bamboo is connected to rose as well: -# -bamboo|ps|PS|S|panasonic|Panasonic KX-P4455 PostScript v51.4:\ - :lp=:rm=rose:rp=bamboo:sd=/var/spool/lpd/bamboo: - - Then, we just need to make spooling directories on - orchid: - - &prompt.root; mkdir -p /var/spool/lpd/rattan /var/spool/lpd/bamboo -&prompt.root; chmod 770 /var/spool/lpd/rattan /var/spool/lpd/bamboo -&prompt.root; chown daemon:daemon /var/spool/lpd/rattan /var/spool/lpd/bamboo - - Now, users on orchid can print to - rattan and bamboo. - If, for example, a user on orchid - typed: - - &prompt.user; lpr -P bamboo -d sushi-review.dvi - - the LPD system on - orchid would copy the job to the spooling - directory /var/spool/lpd/bamboo and - note that it was a DVI job. As soon as the host - rose has room in its - bamboo spooling directory, the two - LPDs would transfer the file to - rose. The file would wait in - rose's queue until it was finally printed. - It would be converted from DVI to &postscript; (since - bamboo is a &postscript; printer) on - rose. - - - - Printers with Networked Data Stream Interfaces - - Often, when you buy a network interface card for a - printer, you can get two versions: one which emulates a - spooler (the more expensive version), or one which just lets - you send data to it as if - you were using a serial or parallel port (the cheaper - version). This section tells how to use the cheaper - version. For the more expensive one, see the previous - section Printers Installed - on Remote Hosts. - - The format of the /etc/printcap - file lets you specify what serial or parallel interface to - use, and (if you are using a serial interface), what baud - rate, whether to use flow control, delays for tabs, - conversion of newlines, and more. But there is no way to - specify a connection to a printer that is listening on a - TCP/IP or other network port. - - To send data to a networked printer, you need to develop - a communications program that can be called by the text and - conversion filters. Here is one such example: the script - netprint takes all data on standard input - and sends it to a network-attached printer. We specify the - hostname of the printer as the first argument and the port - number to which to connect as the second argument to - netprint. Note that this supports - one-way communication only (&os; to printer); many network - printers support two-way communication, and you might want - to take advantage of that (to get printer status, perform - accounting, etc.). - - #!/usr/bin/perl -# -# netprint - Text filter for printer attached to network -# Installed in /usr/local/libexec/netprint -# -$#ARGV eq 1 || die "Usage: $0 <printer-hostname> <port-number>"; - -$printer_host = $ARGV[0]; -$printer_port = $ARGV[1]; - -require 'sys/socket.ph'; - -($ignore, $ignore, $protocol) = getprotobyname('tcp'); -($ignore, $ignore, $ignore, $ignore, $address) - = gethostbyname($printer_host); - -$sockaddr = pack('S n a4 x8', &AF_INET, $printer_port, $address); - -socket(PRINTER, &PF_INET, &SOCK_STREAM, $protocol) - || die "Can't create TCP/IP stream socket: $!"; -connect(PRINTER, $sockaddr) || die "Can't contact $printer_host: $!"; -while (<STDIN>) { print PRINTER; } -exit 0; - - We can then use this script in various filters. Suppose - we had a Diablo 750-N line printer connected to the network. - The printer accepts data to print on port number 5100. The - host name of the printer is scrivener. - Here is the text filter for the printer: - - #!/bin/sh -# -# diablo-if-net - Text filter for Diablo printer `scrivener' listening -# on port 5100. Installed in /usr/local/libexec/diablo-if-net -# -exec /usr/libexec/lpr/lpf "$@" | /usr/local/libexec/netprint scrivener 5100 - + This multiple queue technique can be used to provide + direct access to all kinds of printer features. A printer + with a duplexer could use two queues, one for ordinary + single-sided printing, and one with a filter that sends the + command sequence to enable double-sided printing and then + sends the incoming file. - - Restricting Printer Usage + + Monitoring and Controlling Printing - - printers - restricting access to - - This section gives information on restricting printer - usage. The LPD system lets you - control who can access a printer, both locally or remotely, - whether they can print multiple copies, how large their jobs - can be, and how large the printer queues can get. + Several utilities are available to monitor print jobs and + check and control printer operation. - - Restricting Multiple Copies + + &man.lpq.1; - The LPD system makes it easy - for users to print multiple copies of a file. Users can - print jobs with lpr -#5 - (for example) and get five copies of each file in the job. - Whether this is a good thing is up to you. + &man.lpq.1; shows the status of a user's print + jobs. Print jobs from other users are not shown. - If you feel multiple copies cause unnecessary wear and - tear on your printers, you can disable the - option to &man.lpr.1; by adding the - sc capability to the - /etc/printcap file. When users submit - jobs with the option, they will - see: - - lpr: multiple copies are not allowed - - Note that if you have set up access to a printer - remotely (see section Printers - Installed on Remote Hosts), you need the - sc capability on the remote - /etc/printcap files as well, or else - users will still be able to submit multiple-copy jobs by - using another host. - - Here is an example. This is the - /etc/printcap file for the host - rose. The printer - rattan is quite hearty, so we will allow - multiple copies, but the laser - printer bamboo is a bit more delicate, so - we will disable multiple copies by adding the - sc capability: - - # -# /etc/printcap for host rose - restrict multiple copies on bamboo -# -rattan|line|diablo|lp|Diablo 630 Line Printer:\ - :sh:sd=/var/spool/lpd/rattan:\ - :lp=/dev/lpt0:\ - :if=/usr/local/libexec/if-simple: - -bamboo|ps|PS|S|panasonic|Panasonic KX-P4455 PostScript v51.4:\ - :sh:sd=/var/spool/lpd/bamboo:sc:\ - :lp=/dev/ttyu5:ms#-parenb cs8 clocal crtscts:rw:\ - :if=/usr/local/libexec/psif:\ - :df=/usr/local/libexec/psdf: - - Now, we also need to add the sc - capability on the host orchid's - /etc/printcap (and while we are at it, - let us disable multiple copies for the printer - teak): - - # -# /etc/printcap for host orchid - no multiple copies for local -# printer teak or remote printer bamboo -teak|hp|laserjet|Hewlett Packard LaserJet 3Si:\ - :lp=/dev/lpt0:sd=/var/spool/lpd/teak:mx#0:sc:\ - :if=/usr/local/libexec/ifhp:\ - :vf=/usr/local/libexec/vfhp:\ - :of=/usr/local/libexec/ofhp: - -rattan|line|diablo|lp|Diablo 630 Line Printer:\ - :lp=:rm=rose:rp=rattan:sd=/var/spool/lpd/rattan: - -bamboo|ps|PS|S|panasonic|Panasonic KX-P4455 PostScript v51.4:\ - :lp=:rm=rose:rp=bamboo:sd=/var/spool/lpd/bamboo:sc: - - By using the sc capability, we - prevent the use of lpr - -#, but that still - does not prevent users from running &man.lpr.1; multiple - times, or from submitting the same file multiple times in - one job like this: - - &prompt.user; lpr forsale.sign forsale.sign forsale.sign forsale.sign forsale.sign - - There are many ways to prevent this abuse (including - ignoring it) which you are free to explore. - - - - Restricting Access to Printers - - You can control who can print to what printers by using - the &unix; group mechanism and the rg - capability in /etc/printcap. Just - place the users you want to have access to a printer in a - certain group, and then name that group in the - rg capability. - - If users outside the group (including - root) try to print to the controlled - printer then they will be greeted with the following - message: - - lpr: Not a member of the restricted group - - As with the sc (suppress multiple - copies) capability, you need to specify - rg on remote hosts that also have access - to your printers, if you feel it is appropriate (see section - Printers - Installed on Remote Hosts). - - For example, we will let anyone access the printer - rattan, but only those in group - artists can use - bamboo. Here is the familiar - /etc/printcap for host - rose: - - # -# /etc/printcap for host rose - restricted group for bamboo -# -rattan|line|diablo|lp|Diablo 630 Line Printer:\ - :sh:sd=/var/spool/lpd/rattan:\ - :lp=/dev/lpt0:\ - :if=/usr/local/libexec/if-simple: - -bamboo|ps|PS|S|panasonic|Panasonic KX-P4455 PostScript v51.4:\ - :sh:sd=/var/spool/lpd/bamboo:sc:rg=artists:\ - :lp=/dev/ttyu5:ms#-parenb cs8 clocal crtscts:rw:\ - :if=/usr/local/libexec/psif:\ - :df=/usr/local/libexec/psdf: - - Let us leave the other example - /etc/printcap file (for the host - orchid) alone. Of course, anyone on - orchid can print to - bamboo. It - might be the case that we only allow certain logins on - orchid anyway, and want them to have access - to the printer. Or not. - - - There can be only one restricted group per - printer. - - - - - Controlling Sizes of Jobs Submitted - - print jobs - If you have many users accessing the printers, you - probably need to put an upper limit on the sizes of the - files users can submit to print. After all, there is only - so much free space on the filesystem that houses the - spooling directories, and you also need to make sure there - is room for the jobs of other users. - - - print jobs - controlling - - LPD enables you to limit the - maximum byte size a file in a job can be with the - mx capability. The units are in - BUFSIZ blocks, which are 1024 bytes. If - you put a zero for this capability, there will be no limit - on file size; however, if no mx - capability is specified, then a default limit of 1000 blocks - will be used. - - - The limit applies to files in a - job, and not the total job - size. - - - LPD will not refuse a file - that is larger than the limit you place on a printer. - Instead, it will queue as much of the file up to the limit, - which will then get printed. The rest will be discarded. - Whether this is correct behavior is up for debate. - - Let us add limits to our example printers - rattan and bamboo. - Since those artists' &postscript; - files tend to be large, we will limit them to five - megabytes. We will put no limit on the plain text line + Show the current user's pending jobs on a single printer: - # -# /etc/printcap for host rose -# + &prompt.user; lpq -Plp +Rank Owner Job Files Total Size +1st jsmith 0 (standard input) 12792 bytes -# -# No limit on job size: -# -rattan|line|diablo|lp|Diablo 630 Line Printer:\ - :sh:mx#0:sd=/var/spool/lpd/rattan:\ - :lp=/dev/lpt0:\ - :if=/usr/local/libexec/if-simple: + Show the current user's pending jobs on all + printers: -# -# Limit of five megabytes: -# -bamboo|ps|PS|S|panasonic|Panasonic KX-P4455 PostScript v51.4:\ - :sh:sd=/var/spool/lpd/bamboo:sc:rg=artists:mx#5000:\ - :lp=/dev/ttyu5:ms#-parenb cs8 clocal crtscts:rw:\ - :if=/usr/local/libexec/psif:\ - :df=/usr/local/libexec/psdf: + &prompt.user; lpq -a +lp: +Rank Owner Job Files Total Size +1st jsmith 1 (standard input) 27320 bytes - Again, the limits apply to the local users only. If you - have set up access to your printers remotely, remote users - will not get those limits. You will need to specify the - mx capability in the remote - /etc/printcap files as well. See - section Printers Installed - on Remote Hosts for more information on remote - printing. - - There is another specialized way to limit job sizes from - remote printers; see section Restricting - Jobs from Remote Hosts. +laser: +Rank Owner Job Files Total Size +1st jsmith 287 (standard input) 22443 bytes - - Restricting Jobs from Remote Hosts + + &man.lprm.1; - The LPD spooling system - provides several ways to restrict print jobs submitted from - remote hosts: + &man.lprm.1; is used to remove print jobs. Normal users + are only allowed to remove their own jobs. + root can remove + any or all jobs. - - - Host restrictions + Remove all pending jobs from a printer: - - You can control from which remote hosts a local - LPD accepts requests with - the files /etc/hosts.equiv and - /etc/hosts.lpd. - LPD checks to see if an - incoming request is from a host listed in either one - of these files. If not, - LPD refuses the - request. + &prompt.root; lprm -Plp - +dfA002smithy dequeued +cfA002smithy dequeued +dfA003smithy dequeued +cfA003smithy dequeued +dfA004smithy dequeued +cfA004smithy dequeued - The format of these files is simple: one host name - per line. Note that the file - /etc/hosts.equiv is also used by - the &man.ruserok.3; protocol, and affects programs - like &man.rsh.1; and &man.rcp.1;, so be - careful. + Remove a single job from a + printer. &man.lpq.1; is used to find the job number. - For example, here is the - /etc/hosts.lpd file on the host - rose: + &prompt.user; lpq +Rank Owner Job Files Total Size +1st jsmith 5 (standard input) 12188 bytes +&prompt.user; lprm -Plp 5 +dfA005smithy dequeued +cfA005smithy dequeued + - orchid -violet -madrigal.fishbaum.de + + &man.lpc.8; - This means rose will accept - requests from the hosts orchid, - violet, and madrigal.fishbaum.de. If any - other host tries to access rose's - LPD, the job will be - refused. - - + &man.lpc.8; is used to check and modify printer status. + lpc is followed by a command and an + optional printer name. all can be used + instead of a specific printer name, and the command will be + applied to all printers. Normal users can view status with + &man.lpc.8;. Only + class="username">root can use + commands which modify printer status. - - Size restrictions + Show the status of all printers: - - You can control how much free space there needs to - remain on the filesystem where a spooling directory - resides. Make a file called - minfree in the spooling - directory for the local printer. Insert in that file - a number representing how many disk blocks (512 bytes) - of free space there has to be for a remote job to be - accepted. + &prompt.user; lpc status all +lp: + queuing is enabled + printing is enabled + 1 entry in spool area + printer idle +laser: + queuing is enabled + printing is enabled + 1 entry in spool area + waiting for laser to come up - This lets you insure that remote users will not - fill your filesystem. You can also use it to give a - certain priority to local users: they will be able to - queue jobs long after the free disk space has fallen - below the amount specified in the - minfree file. + Prevent a printer from accepting new jobs, then begin + accepting new jobs again: - For example, let us add a - minfree file for the printer - bamboo. We examine - /etc/printcap to find the - spooling directory for this printer; here is - bamboo's entry: + &prompt.root; lpc disable lp +lp: + queuing disabled +&prompt.root; lpc enable lp +lp: + queuing enabled - bamboo|ps|PS|S|panasonic|Panasonic KX-P4455 PostScript v51.4:\ - :sh:sd=/var/spool/lpd/bamboo:sc:rg=artists:mx#5000:\ - :lp=/dev/ttyu5:ms#-parenb cs8 clocal crtscts:rw:mx#5000:\ - :if=/usr/local/libexec/psif:\ - :df=/usr/local/libexec/psdf: + Stop printing, but continue to accept new jobs. Then + begin printing again: - The spooling directory is given in the - sd capability. We will make three - megabytes (which is 6144 disk blocks) the amount of - free disk space that must exist on the filesystem for - LPD to accept remote - jobs: + &prompt.root; lpc stop lp +lp: + printing disabled +&prompt.root; lpc start lp +lp: + printing enabled + daemon started - &prompt.root; echo 6144 > /var/spool/lpd/bamboo/minfree - - + Restart a printer after some error condition: - - User restrictions + &prompt.root; lpc restart lp +lp: + no daemon to abort + printing enabled + daemon restarted - - You can control which remote users can print to - local printers by specifying the rs - capability in /etc/printcap. - When rs appears in the entry for a - locally-attached printer, - LPD will accept jobs from - remote hosts if the user - submitting the job also has an account of the same - login name on the local host. Otherwise, - LPD refuses the job. + Turn the print queue off and disable printing, with a + message to explain the problem to users: - This capability is particularly useful in an - environment where there are (for example) different - departments sharing a network, and some users - transcend departmental boundaries. By giving them - accounts on your systems, they can use your printers - from their own departmental systems. If you would - rather allow them to use only - your printers and not your computer resources, you can - give them token accounts, with no home - directory and a useless shell like - /usr/bin/false. - - - + &prompt.root; lpc down lp Repair parts will arrive on Monday +lp: + printer and queuing disabled + status message is now: Repair parts will arrive on Monday + + Re-enable a printer that is down: + + &prompt.root; lpc up lp +lp: + printing enabled + daemon started + + See &man.lpc.8; for more commands and options. - - Accounting for Printer Usage + + Shared Printers - - accounting - printer - - So, you need to charge for printouts. And why not? Paper - and ink cost money. And then there are maintenance - costs—printers are loaded with moving parts and tend to - break down. You have examined your printers, usage patterns, - and maintenance fees and have come up with a per-page (or - per-foot, per-meter, or per-whatever) cost. Now, how do you - actually start accounting for printouts? + Printers are often shared by multiple users in businesses + and schools. Additional features are provided to make sharing + printers more convenient. - Well, the bad news is the LPD - spooling system does not provide much help in this department. - Accounting is highly dependent on the kind of printer in use, - the formats being printed, and your - equirements in charging for printer usage. + + Aliases - To implement accounting, you have to modify a printer's - text filter (to charge for plain text jobs) and the conversion - filters (to charge for other file formats), to count pages or - query the printer for pages printed. You cannot get away with - using the simple output filter, since it cannot do accounting. - See section Filters. + The printer name is set in the first line of the + entry in /etc/printcap. Additional + names, or aliases, can be added after + that name. Aliases are separated from the name and each + other by vertical bars: - Generally, there are two ways to do accounting: + lp|repairsprinter|salesprinter:\ - - - Periodic accounting is the more - common way, possibly because it is easier. Whenever - someone prints a job, the filter logs the user, host, and - number of pages to an accounting file. Every month, - semester, year, or whatever time period you prefer, you - collect the accounting files for the various printers, - tally up the pages printed by users, and charge for usage. - Then you truncate all the logging files, starting with - a clean slate for the next period. - + Aliases can be used in place of the printer name. For + example, users in the Sales department print to their + printer with - - Timely accounting is less common, - probably because it is more difficult. This method has - the filters charge users for printouts as soon as they use - the printers. Like disk quotas, the accounting is - immediate. You can prevent users from printing when their - account goes in the red, and might provide a way for users - to check and adjust their print quotas. - But this method requires some database code to track users - and their quotas. - - + &prompt.user; lpr -Psalesprinter sales-report.txt - The LPD spooling system - supports both methods easily: since you have to provide the - filters (well, most of the time), you also have to provide the - accounting code. But there is a bright side: you have - enormous flexibility in your accounting methods. For example, - you choose whether to use periodic or timely accounting. You - choose what information to log: user names, host names, job - types, pages printed, square footage of paper used, how long - the job took to print, and so forth. And you do so by - modifying the filters to save this information. + Users in the Repairs department print to + their printer with - - Quick and Dirty Printer Accounting + &prompt.user; lpr -Prepairsprinter repairs-report.txt - &os; comes with two programs that can get you set up - with simple periodic accounting right away. They are the - text filter lpf, described in section - lpf: a Text - Filter, and &man.pac.8;, a program to gather and - total entries from printer accounting files. - - As mentioned in the section on filters (Filters), - LPD starts the text and the - conversion filters with the name of the accounting file to - use on the filter command line. The filters can use this - argument to know where to write an accounting file entry. - The name of this file comes from the af - capability in /etc/printcap, and if not - specified as an absolute path, is relative to the spooling - directory. - - LPD starts - lpf with page width and length arguments - (from the pw and pl - capabilities). The lpf filter uses these - arguments to determine how much paper will be used. After - sending the file to the printer, it then writes an - accounting entry in the accounting file. The entries look - like this: - - 2.00 rose:andy -3.00 rose:kelly -3.00 orchid:mary -5.00 orchid:mary -2.00 orchid:zhang - - You should use a separate accounting file for each - printer, as lpf has no file locking logic - built into it, and two lpfs might corrupt - each other's entries if they were to write to the same file - at the same time. An easy way to insure a separate - accounting file for each printer is to use - af=acct in - /etc/printcap. Then, each accounting - file will be in the spooling directory for a printer, in a - file named acct. - - When you are ready to charge users for printouts, run - the &man.pac.8; program. Just change to the spooling - directory for the printer you want to collect on and type - pac. You will get a dollar-centric - summary like the following: - - Login pages/feet runs price -orchid:kelly 5.00 1 $ 0.10 -orchid:mary 31.00 3 $ 0.62 -orchid:zhang 9.00 1 $ 0.18 -rose:andy 2.00 1 $ 0.04 -rose:kelly 177.00 104 $ 3.54 -rose:mary 87.00 32 $ 1.74 -rose:root 26.00 12 $ 0.52 - -total 337.00 154 $ 6.74 - - These are the arguments &man.pac.8; expects: - - - - - - - Which printer to - summarize. This option works only if there is an - absolute path in the af capability - in /etc/printcap. - - - - - - - - Sort the output by cost instead of alphabetically - by user name. - - - - - - - - Ignore host name in the accounting files. With - this option, user smith on host - alpha is the same user - smith on host - gamma. Without, they are different - users. - - - - - - - - Compute charges with - price dollars per page or - per foot instead of the price from the - pc capability in - /etc/printcap, or two cents (the - default). You can specify - price as a floating point - number. - - - - - - - - Reverse the sort order. - - - - - - - - Make an accounting summary file and truncate the - accounting file. - - - - - name - … - - - Print accounting information for the given user - names only. - - - - - In the default summary that &man.pac.8; produces, you - see the number of pages printed by each user from various - hosts. If, at your site, host does not matter (because - users can use any host), run pac - -m, to produce the following - summary: - - Login pages/feet runs price -andy 2.00 1 $ 0.04 -kelly 182.00 105 $ 3.64 -mary 118.00 35 $ 2.36 -root 26.00 12 $ 0.52 -zhang 9.00 1 $ 0.18 - -total 337.00 154 $ 6.74 - - - To compute the dollar amount due, - &man.pac.8; uses the pc capability in the - /etc/printcap file (default of 200, or - 2 cents per page). Specify, in hundredths of cents, the - price per page or per foot you want to charge for printouts - in this capability. You can override this value when you - run &man.pac.8; with the option. The - units for the option are in dollars, - though, not hundredths of cents. For example, - - &prompt.root; pac -p1.50 - - makes each page cost one dollar and fifty cents. You - can really rake in the profits by using this option. - - Finally, running pac - -s will - save the summary information in a summary accounting file, - which is named the same as the printer's accounting file, - but with _sum appended to the name. It - then truncates the accounting file. When you run - &man.pac.8; again, it rereads the summary file to get - starting totals, then adds information from the regular - accounting file. + All of the documents print on that single printer. When + the Sales department grows enough to need their own printer, + the alias is removed from the shared printer entry and used + as the name of the new printer. Users in both departments + continue to use the same commands, but the Sales documents + are sent to the new printer. - - How Can You Count Pages Printed? + + Header Pages - In order to perform even remotely accurate accounting, - you need to be able to determine how much paper a job uses. - This is the essential problem of printer accounting. + Users can have difficulty locating their documents in + the stack of pages produced by a busy shared printer. + Header pages were created to solve this + problem. A header page with the user name and document name + is printed before each print job. These pages are also + sometimes called banner or + separator pages. - For plain text jobs, the problem is not that hard to - solve: you count how many lines are in a job and compare it - to how many lines per page your printer supports. Do not - forget to take into account backspaces in the file which - overprint lines, or long logical lines that wrap onto one or - more additional physical lines. + Enabling header pages differs depending on whether the + printer is connected directly to the computer with a + USB, parallel, or serial cable, or + is connected remotely by the network. - The text filter lpf (introduced in - lpf: a Text - Filter) takes into account these things when it - does accounting. If you are writing a text filter which - needs to do accounting, you might want to examine - lpf's source code. + Header pages on directly-connected printers are enabled + by removing the :sh:\ (Suppress Header) + line from the entry in /etc/printcap. + These header pages only use line feed characters for new + lines. Some printers will need the + /usr/share/examples/printing/hpif + filter to prevent stairstepped text. The filter configures + PCL printers to print both carriage + returns and line feeds when a line feed is received. - How do you handle other file formats, though? - - Well, for DVI-to-LaserJet or DVI-to-&postscript; - conversion, you can have your filter parse the diagnostic - output of dvilj or - dvips and look to see how many pages were - converted. You might be able to do similar things with - other file formats and conversion programs. - - But these methods suffer from the fact that the printer - may not actually print all those pages. For example, it - could jam, run out of toner, or explode—and the user - would still get charged. - - So, what can you do? - - There is only one sure way to do - accurate accounting. Get a printer - that can tell you how much paper it uses, and attach it via - a serial line or a network connection. Nearly all - &postscript; printers support this notion. Other makes and - models do as well (networked Imagen laser printers, for - example). Modify the filters for these printers to get the - page usage after they print each job and have them log - accounting information based on that value - only. There is no line counting nor - error-prone file examination required. - - Of course, you can always be generous and make all - printouts free. + Header pages for network printers must be configured on + the printer itself. Header page entries in + /etc/printcap are ignored. Settings + are usually available from the printer front panel or a + configuration web page accessible with a web browser. + + + + + References + + Example files: /usr/share/examples/printing/. + + The 4.3BSD Line Printer Spooler + Manual, + /usr/share/doc/smm/07.lpd/paper.ascii.gz. + + Manual pages: &man.printcap.5;, &man.lpd.8;, &man.lpr.1;, + &man.lpc.8;, &man.lprm.1;, &man.lpq.1;. - - Using Printers + + Other Printing Systems - - printers - usage - - This section tells you how to use printers you have set up - with &os;. Here is an overview of the user-level - commands: + Several other printing systems are available in + addition to the built-in &man.lpd.8;. These systems + offer support for other protocols or additional features. - - - &man.lpr.1; + + <acronym>CUPS</acronym> (Common &unix; Printing + System) - - Print jobs - - - - - &man.lpq.1; - - - Check printer queues - - - - - &man.lprm.1; - - - Remove jobs from a printer's queue - - - - - There is also an administrative command, &man.lpc.8;, - described in the section Administering Printers, used to - control printers and their queues. - - All three of the commands &man.lpr.1;, &man.lprm.1;, and - &man.lpq.1; accept an option to specify - on which printer/queue to operate, as listed in the - /etc/printcap file. This enables you to - submit, remove, and check on jobs for various printers. If you - do not use the option, then these commands - use the printer specified in the PRINTER - environment variable. Finally, if you do not have a - PRINTER environment variable, these commands - default to the printer named lp. - - Hereafter, the terminology default - printer means the printer named in the - PRINTER environment variable, or the printer - named lp when there is no - PRINTER environment variable. - - - Printing Jobs - - To print files, type: - - &prompt.user; lpr filename ... - - printing - This prints each of the listed files to the default - printer. If you list no files, &man.lpr.1; reads data to - print from standard input. For example, this command prints - some important system files: - - &prompt.user; lpr /etc/host.conf /etc/hosts.equiv - - To select a specific printer, type: - - &prompt.user; lpr -P printer-name filename ... - - This example prints a long listing of the current - directory to the printer named - rattan: - - &prompt.user; ls -l | lpr -P rattan - - Because no files were listed for the &man.lpr.1; command, - lpr read the data to print from standard - input, which was the output of the ls - -l command. - - The &man.lpr.1; command can also accept a wide variety of - options to control formatting, apply file conversions, - generate multiple copies, and so forth. For more information, - see the section Printing - Options. + CUPS is a popular printing system + available on many operating systems. Using + CUPS on &os; is documented in a separate + article: - - Checking Jobs + + HPLIP - print jobs - When you print with &man.lpr.1;, the data you wish to - print is put together in a package called a print - job, which is sent to the - LPD spooling system. Each printer - has a queue of jobs, and your job waits in that queue along - with other jobs from yourself and from other users. The - printer prints those jobs in a first-come, first-served - order. - - To display the queue for the default printer, type - &man.lpq.1;. For a specific printer, use the - option. For example, the command - - &prompt.user; lpq -P bamboo - - shows the queue for the printer named - bamboo. Here is an example of the output - of the lpq command: - - bamboo is ready and printing -Rank Owner Job Files Total Size -active kelly 9 /etc/host.conf, /etc/hosts.equiv 88 bytes -2nd kelly 10 (standard input) 1635 bytes -3rd mary 11 ... 78519 bytes - - This shows three jobs in the queue for - bamboo. The first job, submitted by user - kelly, got assigned job number 9. Every job - for a printer gets a unique job number. Most of the time you - can ignore the job number, but you will need it if you want to - cancel the job; see section Removing Jobs for - details. - - Job number nine consists of two files; multiple files - given on the &man.lpr.1; command line are treated as part of a - single job. It is the currently active job (note the word - active under the Rank - column), which means the printer should be currently printing - that job. The second job consists of data passed as the - standard input to the &man.lpr.1; command. The third job came - from user mary; it is a much larger job. - The pathname of the file she is trying to print is too long to - fit, so the &man.lpq.1; command just shows three dots. - - The very first line of the output from &man.lpq.1; is also - useful: it tells what the printer is currently doing (or at - least what LPD thinks the printer - is doing). - - The &man.lpq.1; command also support a - option to generate a detailed long listing. Here is an - example of lpq -l: - - waiting for bamboo to become ready (offline ?) -kelly: 1st [job 009rose] - /etc/host.conf 73 bytes - /etc/hosts.equiv 15 bytes - -kelly: 2nd [job 010rose] - (standard input) 1635 bytes - -mary: 3rd [job 011rose] - /home/orchid/mary/research/venus/alpha-regio/mapping 78519 bytes + Hewlett Packard provides a printing system that supports + many of their inkjet and laser printers. The port is + print/hplip. The main web page + is at . + The port handles all the installation details on &os;. + Configuration information is shown at . - - Removing Jobs + + LPRng - If you change your mind about printing a job, you can - remove the job from the queue with the &man.lprm.1; command. - Often, you can even use &man.lprm.1; to remove an active job, - but some or all of the job might still get printed. - - To remove a job from the default printer, first use - &man.lpq.1; to find the job number. Then type: - - &prompt.user; lprm job-number - - To remove the job from a specific printer, add the - option. The following command removes job - number 10 from the queue for the printer - bamboo: - - &prompt.user; lprm -P bamboo 10 - - The &man.lprm.1; command has a few shortcuts: - - - - lprm - - - - Removes all jobs (for the default printer) belonging - to you. - - - - - lprm user - - - Removes all jobs (for the default printer) belonging - to user. The superuser can - remove other users' jobs; you can remove only your own - jobs. - - - - - lprm - - - With no job number, user name, or - appearing on the command line, &man.lprm.1; removes the - currently active job on the default printer, if it - belongs to you. The superuser can remove any active - job. - - - - - Just use the option with the above - shortcuts to operate on a specific printer instead of the - default. For example, the following command removes all jobs - for the current user in the queue for the printer named - rattan: - - &prompt.user; lprm -P rattan - - - - If you are working in a networked environment, - &man.lprm.1; will let you remove jobs only from the host - from which the jobs were submitted, even if the same printer - is available from other hosts. The following command - sequence demonstrates this: - - &prompt.user; lpr -P rattan myfile -&prompt.user; rlogin orchid -&prompt.user; lpq -P rattan -Rank Owner Job Files Total Size -active seeyan 12 ... 49123 bytes -2nd kelly 13 myfile 12 bytes -&prompt.user; lprm -P rattan 13 -rose: Permission denied -&prompt.user; logout -&prompt.user; lprm -P rattan 13 -dfA013rose dequeued -cfA013rose dequeued - + LPRng was developed as an + enhanced alternative to &man.lpd.8;. The port is + sysutils/LPRng. For details + and documentation, see + . - - - Beyond Plain Text: Printing Options - - The &man.lpr.1; command supports a number of options that - control formatting text, converting graphic and other file - formats, producing multiple copies, handling of the job, and - more. This section describes the options. - - - Formatting and Conversion Options - - The following &man.lpr.1; options control formatting of - the files in the job. Use these options if the job does not - contain plain text or if you want plain text formatted - through the &man.pr.1; utility. - - &tex; - For example, the following command prints a DVI file - (from the &tex; typesetting system) named - fish-report.dvi - to the printer named bamboo: - - &prompt.user; lpr -P bamboo -d fish-report.dvi - - These options apply to every file in the job, so you - cannot mix (say) DVI and ditroff files together in a job. - Instead, submit the files as separate jobs, using a - different conversion option for each job. - - - All of these options except and - require conversion filters installed - for the destination printer. For example, the - option requires the DVI conversion - filter. Section Conversion - Filters gives details. - - - - - - - - Print cifplot files. - - - - - - - - Print DVI files. - - - - - - - - Print FORTRAN text files. - - - - - - - - Print plot data. - - - - - - - - Indent the output by - number columns; if you omit - number, indent by 8 - columns. This option works only with certain - conversion filters. - - - Do not put any space between the - and the number. - - - - - - - - - Print literal text data, including control - characters. - - - - - - - - Print ditroff (device independent troff) - data. - - - - - -p - - - Format plain text with &man.pr.1; before printing. - See &man.pr.1; for more information. - - - - - - - - Use title on the - &man.pr.1; header instead of the file name. This - option has effect only when used with the - - option. - - - - - - - - Print troff data. - - - - - - - - Print raster data. - - - - - Here is an example: this command prints a nicely - formatted version of the &man.ls.1; manual page on the - default printer: - - &prompt.user; zcat /usr/share/man/man1/ls.1.gz | troff -t -man | lpr -t - - The &man.zcat.1; command uncompresses the source of the - &man.ls.1; manual page and passes it to the &man.troff.1; - command, which formats that source and makes GNU troff - output and passes it to &man.lpr.1;, which submits the job - to the LPD spooler. Because we - used the option to &man.lpr.1;, the - spooler will convert the GNU troff output into a format the - default printer can understand when it prints the - job. - - - - Job Handling Options - - The following options to &man.lpr.1; tell - LPD to handle the job - specially: - - - - -# copies - - - Produce a number of - copies of each file in the - job instead of just one copy. An administrator may - disable this option to reduce printer wear-and-tear - and encourage photocopier usage. See section Restricting - Multiple Copies. - - This example prints three copies of - parser.c - followed by three copies of - parser.h - to the default printer: - - &prompt.user; lpr -#3 parser.c parser.h - - - - - -m - - - Send mail after completing the print job. With - this option, the LPD system - will send mail to your account when it finishes - handling your job. In its message, it will tell you - if the job completed successfully or if there was an - error, and (often) what the error was. - - - - - -s - - - Do not copy the files to the spooling directory, - but make symbolic links to them instead. - - If you are printing a large job, you probably want - to use this option. It saves space in the spooling - directory (your job might overflow the free space on - the filesystem where the spooling directory resides). - It saves time as well since - LPD will not have to copy - each and every byte of your job to the spooling - directory. - - There is a drawback, though: since - LPD will refer to the - original files directly, you cannot modify or remove - them until they have been printed. - - - If you are printing to a remote printer, - LPD will eventually have - to copy files from the local host to the remote - host, so the option will save - space only on the local spooling directory, not the - remote. It is still useful, though. - - - - - - -r - - - Remove the files in the job after copying them to - the spooling directory, or after printing them with - the option. Be careful with this - option! - - - - - - - Header Page Options - - These options to &man.lpr.1; adjust the text that - normally appears on a job's header page. If header pages - are suppressed for the destination printer, these options - have no effect. See section Header - Pages - for information about setting up header pages. - - - - -C text - - - Replace the hostname on the header page with - text. The hostname is - normally the name of the host from which the job was - submitted. - - - - - -J text - - - Replace the job name on the header page with - text. The job name is - normally the name of the first file of the job, or - stdin if you are printing - standard input. - - - - - -h - - - Do not print any header page. - - - At some sites, this option may have no effect - due to the way header pages are generated. See - Header - Pages for details. - - - - - - - - - Administering Printers - - As an administrator for your printers, you have had to - install, set up, and test them. Using the &man.lpc.8; - command, you can interact with your printers in yet more ways. - With &man.lpc.8;, you can - - - - Start and stop the printers - - - - Enable and disable their queues - - - - Rearrange the order of the jobs in each queue. - - - - First, a note about terminology: if a printer is - stopped, it will not print anything in - its queue. Users can still submit jobs, which will wait in - the queue until the printer is started or - the queue is cleared. - - If a queue is disabled, no user - (except root) can submit jobs for the - printer. An enabled queue allows jobs to - be submitted. A printer can be started - for a disabled queue, in which case it will continue to print - jobs in the queue until the queue is empty. - - In general, you have to have root - privileges to use the &man.lpc.8; command. Ordinary users can - use the &man.lpc.8; command to get printer status and to - restart a hung printer only. - - Here is a summary of the &man.lpc.8; commands. Most of - the commands take a printer-name - argument to tell on which printer to operate. You can use - all for the - printer-name to mean all printers - listed in /etc/printcap. - - - - abort - printer-name - - - Cancel the current job and stop the printer. Users - can still submit jobs if the queue is enabled. - - - - - clean - printer-name - - - Remove old files from the printer's spooling - directory. Occasionally, the files that make up a job - are not properly removed by - LPD, particularly if there - have been errors during printing or a lot of - administrative activity. This command finds files that - do not belong in the spooling directory and removes - them. - - - - - disable - printer-name - - - Disable queuing of new jobs. If the printer is - running, it will continue to print any jobs remaining in - the queue. The superuser (root) - can always submit jobs, even to a disabled queue. - - This command is useful while you are testing a new - printer or filter installation: disable the queue and - submit jobs as root. Other users - will not be able to submit jobs until you complete your - testing and re-enable the queue with the - enable command. - - - - - down printer-name - message - - - Take a printer down. Equivalent to - disable followed by - stop. The - message appears as the - printer's status whenever a user checks the printer's - queue with &man.lpq.1; or status with lpc - status. - - - - - enable - printer-name - - - Enable the queue for a printer. Users can submit - jobs but the printer will not print anything until it is - started. - - - - - help - command-name - - - Print help on the command - command-name. With no - command-name, print a summary - of the commands available. - - - - - restart - printer-name - - - Start the printer. Ordinary users can use this - command if some extraordinary circumstance hangs - LPD, but they cannot start - a printer stopped with either the - stop or - down commands. The - restart command is equivalent to - abort followed by - start. - - - - - start - printer-name - - - Start the printer. The printer will print jobs in - its queue. - - - - - stop - printer-name - - - Stop the printer. The printer will finish the - current job and will not print anything else in its - queue. Even though the printer is stopped, users can - still submit jobs to an enabled queue. - - - - - topq printer-name - job-or-username - - - Rearrange the queue for - printer-name by placing the - jobs with the listed job - numbers or the jobs belonging to - username at the top of - the queue. For this command, you cannot use - all as the - printer-name. - - - - - up - printer-name - - - Bring a printer up; the opposite of the - down command. Equivalent to - start followed by - enable. - - - - - &man.lpc.8; accepts the above commands on the command - line. If you do not enter any commands, &man.lpc.8; enters an - interactive mode, where you can enter commands until you type - exit, quit, or - end-of-file. - - - - - Alternatives to the Standard Spooler - - If you have been reading straight through this manual, by - now you have learned just about everything there is to know - about the LPD spooling system that - comes with &os;. You can probably appreciate many of its - shortcomings, which naturally leads to the question: What - other spooling systems are out there (and work with - &os;)? - - - - LPRng - - - LPRngLPRng, which purportedly - means LPR: the Next Generation is a - complete rewrite of PLP. Patrick Powell and Justin Mason - (the principal maintainer of PLP) collaborated to make - LPRng. The main site for - LPRng is http://www.lprng.org/. - - - - - CUPS - - - CUPSCUPS, the Common UNIX - Printing System, provides a portable printing layer for - &unix;-based operating systems. It has been developed by - Easy Software Products to promote a standard printing - solution for all &unix; vendors and users. - - CUPS uses the Internet - Printing Protocol (IPP) as the basis - for managing print jobs and queues. The Line Printer - Daemon (LPD), Server Message Block - (SMB), and AppSocket (aka JetDirect) - protocols are also supported with reduced functionality. - CUPS adds network printer browsing and PostScript Printer - Description (PPD) based printing - options to support real-world printing under - &unix;. - - The main site for CUPS is - http://www.cups.org/. - - - - - HPLIP - - - HPLIPHPLIP, the HP &linux; - Imaging and Printing system, is an HP-developed suite of - programs that supports printing, scanning and fax - facilities for HP appliances. This suite of programs - utilizes the CUPS printing - system as a backend for some of its printing - features. - - The main site for HPLIP - is http://hplipopensource.com/hplip-web/index.html. - - - - - - - Troubleshooting - - After performing the simple test with &man.lptest.1;, you - might have gotten one of the following results instead of the - correct printout: - - - - It worked, after a while; or, it did not eject a full - sheet. - - - The printer printed the above, but it sat for a while - and did nothing. In fact, you might have needed to press - a PRINT REMAINING or FORM FEED button on the printer to - get any results to appear. - - If this is the case, the printer was probably waiting - to see if there was any more data for your job before it - printed anything. To fix this problem, you can have the - text filter send a FORM FEED character (or whatever is - necessary) to the printer. This is usually sufficient to - have the printer immediately print any text remaining in - its internal buffer. It is also useful to make sure each - print job ends on a full sheet, so the next job does not - start somewhere on the middle of the last page of the - previous job. - - The following replacement for the shell script - /usr/local/libexec/if-simple prints - a form feed after it sends the job to the printer: - - #!/bin/sh -# -# if-simple - Simple text input filter for lpd -# Installed in /usr/local/libexec/if-simple -# -# Simply copies stdin to stdout. Ignores all filter arguments. -# Writes a form feed character (\f) after printing job. - -/bin/cat && printf "\f" && exit 0 -exit 2 - - - - - It produced the staircase effect. - - - You got the following on paper: - - !"#$%&'()*+,-./01234 - "#$%&'()*+,-./012345 - #$%&'()*+,-./0123456 - - You have become another victim of the - staircase effect, caused by - conflicting interpretations of what characters should - indicate a new line. &unix; style operating systems use a - single character: ASCIIASCII code 10, the line feed (LF). - &ms-dos;MS-DOS, &os2;OS/2, and others uses a pair of characters, - ASCII code 10 and ASCII code 13 (the - carriage return or CR). Many printers use the &ms-dos; - convention for representing new-lines. - - When you print with &os;, your text used just the line - feed character. The printer, upon seeing a line feed - character, advanced the paper one line, but maintained the - same horizontal position on the page for the next - character to print. That is what the carriage return is - for: to move the location of the next character to print - to the left edge of the paper. - - Here is what &os; wants your printer to do: - - - - - - Printer received CR - Printer prints CR - - - - Printer received LF - Printer prints CR + LF - - - - - - Here are some ways to achieve this: - - - - Use the printer's configuration switches or - control panel to alter its interpretation of these - characters. Check your printer's manual to find out - how to do this. - - - If you boot your system into other operating - systems besides &os;, you may have to - reconfigure the printer to use - a an interpretation for CR and LF characters that - those other operating systems use. You might prefer - one of the other solutions, below. - - - - - Have &os;'s serial line driver automatically - convert LF to CR+LF. Of course, this works with - printers on serial ports only. - To enable this feature, use the ms# - capability and set the onlcr mode - in the /etc/printcap file for the - printer. - - - - Send an escape code to the - printer to have it temporarily treat LF characters - differently. Consult your printer's manual for escape - codes that your printer might support. When you find - the proper escape code, modify the text filter to send - the code first, then send the print job. - - PCL - Here is an example text filter for printers that - understand the Hewlett-Packard PCL escape codes. This - filter makes the printer treat LF characters as a LF - and CR; then it sends the job; then it sends a form - feed to eject the last page of the job. It should - work with nearly all Hewlett Packard printers. - - #!/bin/sh -# -# hpif - Simple text input filter for lpd for HP-PCL based printers -# Installed in /usr/local/libexec/hpif -# -# Simply copies stdin to stdout. Ignores all filter arguments. -# Tells printer to treat LF as CR+LF. Ejects the page when done. - -printf "\033&k2G" && cat && printf "\033&l0H" && exit 0 -exit 2 - - Here is an example - /etc/printcap - from a host called orchid. It has a - single printer attached to its first parallel port, a - Hewlett Packard LaserJet 3Si named - teak. It is using the above script - as its text filter: - - # -# /etc/printcap for host orchid -# -teak|hp|laserjet|Hewlett Packard LaserJet 3Si:\ - :lp=/dev/lpt0:sh:sd=/var/spool/lpd/teak:mx#0:\ - :if=/usr/local/libexec/hpif: - - - - - - - It overprinted each line. - - - The printer never advanced a line. All of the lines - of text were printed on top of each other on one - line. - - This problem is the opposite of the - staircase effect, described above, and is much rarer. - Somewhere, the LF characters that &os; uses to end a line - are being treated as CR characters to return the print - location to the left edge of the paper, but not also down - a line. - - Use the printer's configuration switches or control - panel to enforce the following interpretation of LF and - CR characters: - - - - - - Printer receives - Printer prints - - - - - - CR - CR - - - - LF - CR + LF - - - - - - - - - The printer lost characters. - - - While printing, the printer did not print a few - characters in each line. The problem might have gotten - worse as the printer ran, losing more and more - characters. - - The problem is that the printer cannot keep up with - the speed at which the computer sends data over a serial - line (this problem should not occur with printers on - parallel ports). There are two ways to overcome the - problem: - - - - If the printer supports XON/XOFF flow control, - have &os; use it by specifying the - ixon mode in the - ms# capability. - - - - If the printer supports the Request to Send / - Clear to Send hardware handshake (commonly known as - RTS/CTS), specify the - crtscts mode in the - ms# capability. Make sure the - cable connecting the printer to the computer is - correctly wired for hardware flow control. - - - - - - - It printed garbage. - - - The printer printed what appeared to be random - garbage, but not the desired text. - - This is usually another symptom of incorrect - communications parameters with a serial printer. - Double-check the bps rate in the br - capability, and the parity setting in the - ms# capability; make sure the printer - is using the same settings as specified in the - /etc/printcap file. - - - - - Nothing happened. - - - If nothing happened, the problem is probably within - &os; and not the hardware. Add the log file - (lf) capability to the entry for the - printer you are debugging in the - /etc/printcap file. For example, - here is the entry for rattan, with the - lf capability: - - rattan|line|diablo|lp|Diablo 630 Line Printer:\ - :sh:sd=/var/spool/lpd/rattan:\ - :lp=/dev/lpt0:\ - :if=/usr/local/libexec/if-simple:\ - :lf=/var/log/rattan.log - - Then, try printing again. Check the log file (in our - example, /var/log/rattan.log) to see - any error messages that might appear. Based on the - messages you see, try to correct the problem. - - If you do not specify a lf - capability, LPD uses - /dev/console as a - default. - - -