lp(1p) — Linux manual page


LP(1P)                  POSIX Programmer's Manual                 LP(1P)

PROLOG         top

       This manual page is part of the POSIX Programmer's Manual.  The
       Linux implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior),
       or the interface may not be implemented on Linux.

NAME         top

       lp — send files to a printer

SYNOPSIS         top

       lp [-c] [-d dest] [-n copies] [-msw] [-o option]... [-t title] [file...]

DESCRIPTION         top

       The lp utility shall copy the input files to an output
       destination in an unspecified manner. The default output
       destination should be to a hardcopy device, such as a printer or
       microfilm recorder, that produces non-volatile, human-readable
       documents. If such a device is not available to the application,
       or if the system provides no such device, the lp utility shall
       exit with a non-zero exit status.

       The actual writing to the output device may occur some time after
       the lp utility successfully exits. During the portion of the
       writing that corresponds to each input file, the implementation
       shall guarantee exclusive access to the device.

       The lp utility shall associate a unique request ID with each

       Normally, a banner page is produced to separate and identify each
       print job. This page may be suppressed by implementation-defined
       conditions, such as an operator command or one of the -o option

OPTIONS         top

       The lp utility shall conform to the Base Definitions volume of
       POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines.

       The following options shall be supported:

       -c        Exit only after further access to any of the input
                 files is no longer required. The application can then
                 safely delete or modify the files without affecting the
                 output operation. Normally, files are not copied, but
                 are linked whenever possible. If the -c option is not
                 given, then the user should be careful not to remove
                 any of the files before the request has been printed in
                 its entirety. It should also be noted that in the
                 absence of the -c option, any changes made to the named
                 files after the request is made but before it is
                 printed may be reflected in the printed output.  On
                 some implementations, -c may be on by default.

       -d dest   Specify a string that names the destination (dest).  If
                 dest is a printer, the request shall be printed only on
                 that specific printer. If dest is a class of printers,
                 the request shall be printed on the first available
                 printer that is a member of the class. Under certain
                 conditions (printer unavailability, file space
                 limitation, and so on), requests for specific
                 destinations need not be accepted. Destination names
                 vary between systems.

                 If -d is not specified, and neither the LPDEST nor
                 PRINTER environment variable is set, an unspecified
                 destination is used. The -d dest option shall take
                 precedence over LPDEST, which in turn shall take
                 precedence over PRINTER.  Results are undefined when
                 dest contains a value that is not a valid destination

       -m        Send mail (see mailx(1p)) after the files have been
                 printed. By default, no mail is sent upon normal
                 completion of the print request.

       -n copies Write copies number of copies of the files, where
                 copies is a positive decimal integer. The methods for
                 producing multiple copies and for arranging the
                 multiple copies when multiple file operands are used
                 are unspecified, except that each file shall be output
                 as an integral whole, not interleaved with portions of
                 other files.

       -o option Specify printer-dependent or class-dependent options.
                 Several such options may be collected by specifying the
                 -o option more than once.

       -s        Suppress messages from lp.

       -t title  Write title on the banner page of the output.

       -w        Write a message on the user's terminal after the files
                 have been printed. If the user is not logged in, then
                 mail shall be sent instead.

OPERANDS         top

       The following operand shall be supported:

       file      A pathname of a file to be output. If no file operands
                 are specified, or if a file operand is '-', the
                 standard input shall be used. If a file operand is
                 used, but the -c option is not specified, the process
                 performing the writing to the output device may have
                 user and group permissions that differ from that of the
                 process invoking lp.

STDIN         top

       The standard input shall be used only if no file operands are
       specified, or if a file operand is '-'.  See the INPUT FILES

INPUT FILES         top

       The input files shall be text files.


       The following environment variables shall affect the execution of

       LANG      Provide a default value for the internationalization
                 variables that are unset or null. (See the Base
                 Definitions volume of POSIX.1‐2017, Section 8.2,
                 Internationalization Variables for the precedence of
                 internationalization variables used to determine the
                 values of locale categories.)

       LC_ALL    If set to a non-empty string value, override the values
                 of all the other internationalization variables.

       LC_CTYPE  Determine the locale for the interpretation of
                 sequences of bytes of text data as characters (for
                 example, single-byte as opposed to multi-byte
                 characters in arguments and input files).

                 Determine the locale that should be used to affect the
                 format and contents of diagnostic messages written to
                 standard error and informative messages written to
                 standard output.

       LC_TIME   Determine the format and contents of date and time
                 strings displayed in the lp banner page, if any.

       LPDEST    Determine the destination. If the LPDEST environment
                 variable is not set, the PRINTER environment variable
                 shall be used. The -d dest option takes precedence over
                 LPDEST.  Results are undefined when -d is not specified
                 and LPDEST contains a value that is not a valid
                 destination name.

       NLSPATH   Determine the location of message catalogs for the
                 processing of LC_MESSAGES.

       PRINTER   Determine the output device or destination. If the
                 LPDEST and PRINTER environment variables are not set,
                 an unspecified output device is used. The -d dest
                 option and the LPDEST environment variable shall take
                 precedence over PRINTER.  Results are undefined when -d
                 is not specified, LPDEST is unset, and PRINTER contains
                 a value that is not a valid device or destination name.

       TZ        Determine the timezone used to calculate date and time
                 strings displayed in the lp banner page, if any. If TZ
                 is unset or null, an unspecified default timezone shall
                 be used.



STDOUT         top

       The lp utility shall write a request ID to the standard output,
       unless -s is specified. The format of the message is unspecified.
       The request ID can be used on systems supporting the historical
       cancel and lpstat utilities.

STDERR         top

       The standard error shall be used only for diagnostic messages.

OUTPUT FILES         top




EXIT STATUS         top

       The following exit values shall be returned:

        0    All input files were processed successfully.

       >0    No output device was available, or an error occurred.



       The following sections are informative.


       The pr and fold utilities can be used to achieve reasonable
       formatting for the implementation's default page size.

       A conforming application can use one of the file operands only
       with the -c option or if the file is publicly readable and
       guaranteed to be available at the time of printing. This is
       because POSIX.1‐2008 gives the implementation the freedom to
       queue up the request for printing at some later time by a
       different process that might not be able to access the file.

EXAMPLES         top

        1. To print file file:

               lp -c file

        2. To print multiple files with headers:

               pr file1 file2 | lp

RATIONALE         top

       The lp utility was designed to be a basic version of a utility
       that is already available in many historical implementations. The
       standard developers considered that it should be implementable
       simply as:

           cat "$@" > /dev/lp

       after appropriate processing of options, if that is how the
       implementation chose to do it and if exclusive access could be
       granted (so that two users did not write to the device
       simultaneously).  Although in the future the standard developers
       may add other options to this utility, it should always be able
       to execute with no options or operands and send the standard
       input to an unspecified output device.

       This volume of POSIX.1‐2017 makes no representations concerning
       the format of the printed output, except that it must be ``human-
       readable'' and ``non-volatile''.  Thus, writing by default to a
       disk or tape drive or a display terminal would not qualify. (Such
       destinations are not prohibited when -d dest, LPDEST, or PRINTER
       are used, however.)

       This volume of POSIX.1‐2017 is worded such that a ``print job''
       consisting of multiple input files, possibly in multiple copies,
       is guaranteed to print so that any one file is not intermixed
       with another, but there is no statement that all the files or
       copies have to print out together.

       The -c option may imply a spooling operation, but this is not
       required. The utility can be implemented to wait until the
       printer is ready and then wait until it is finished. Because of
       that, there is no attempt to define a queuing mechanism
       (priorities, classes of output, and so on).

       On some historical systems, the request ID reported on the STDOUT
       can be used to later cancel or find the status of a request using
       utilities not defined in this volume of POSIX.1‐2017.

       Although the historical System V lp and BSD lpr utilities have
       provided similar functionality, they used different names for the
       environment variable specifying the destination printer.  Since
       the name of the utility here is lp, LPDEST (used by the System V
       lp utility) was given precedence over PRINTER (used by the BSD
       lpr utility). Since environments of users frequently contain one
       or the other environment variable, the lp utility is required to
       recognize both. If this was not done, many applications would
       send output to unexpected output devices when users moved from
       system to system.

       Some have commented that lp has far too little functionality to
       make it worthwhile. Requests have proposed additional options or
       operands or both that added functionality. The requests included:

        *  Wording requiring the output to be ``hardcopy''

        *  A requirement for multiple printers

        *  Options for supporting various page-description languages

       Given that a compliant system is not required to even have a
       printer, placing further restrictions upon the behavior of the
       printer is not useful. Since hardcopy format is so application-
       dependent, it is difficult, if not impossible, to select a
       reasonable subset of functionality that should be required on all
       compliant systems.

       The term unspecified is used in this section in lieu of
       implementation-defined as most known implementations would not be
       able to make definitive statements in their conformance
       documents; the existence and usage of printers is very dependent
       on how the system administrator configures each individual

       Since the default destination, device type, queuing mechanisms,
       and acceptable forms of input are all unspecified, usage
       guidelines for what a conforming application can do are as

        *  Use the command in a pipeline, or with -c, so that there are
           no permission problems and the files can be safely deleted or

        *  Limit output to text files of reasonable line lengths and
           printable characters and include no device-specific
           formatting information, such as a page description language.
           The meaning of ``reasonable'' in this context can only be
           answered as a quality-of-implementation issue, but it should
           be apparent from historical usage patterns in the industry
           and the locale. The pr and fold utilities can be used to
           achieve reasonable formatting for the default page size of
           the implementation.

       Alternatively, the application can arrange its installation in
       such a way that it requires the system administrator or operator
       to provide the appropriate information on lp options and
       environment variable values.

       At a minimum, having this utility in this volume of POSIX.1‐2017
       tells the industry that conforming applications require a means
       to print output and provides at least a command name and LPDEST
       routing mechanism that can be used for discussions between
       vendors, application developers, and users. The use of ``should''
       in the DESCRIPTION of lp clearly shows the intent of the standard
       developers, even if they cannot mandate that all systems (such as
       laptops) have printers.

       This volume of POSIX.1‐2017 does not specify what the ownership
       of the process performing the writing to the output device may
       be. If -c is not used, it is unspecified whether the process
       performing the writing to the output device has permission to
       read file if there are any restrictions in place on who may read
       file until after it is printed. Also, if -c is not used, the
       results of deleting file before it is printed are unspecified.



SEE ALSO         top


       The Base Definitions volume of POSIX.1‐2017, Chapter 8,
       Environment Variables, Section 12.2, Utility Syntax Guidelines

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 by the Institute of Electrical and Electronics
       Engineers, Inc and The Open Group.  In the event of any
       discrepancy between this version and the original IEEE and The
       Open Group Standard, the original IEEE and The Open Group
       Standard is the referee document. The original Standard can be
       obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page
       are most likely to have been introduced during the conversion of
       the source files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group               2017                            LP(1P)

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