1LP(1P) POSIX Programmer's Manual LP(1P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
12 lp — send files to a printer
13
15 lp [-c] [-d dest] [-n copies] [-msw] [-o option]... [-t title] [file...]
16
18 The lp utility shall copy the input files to an output destination in
19 an unspecified manner. The default output destination should be to a
20 hardcopy device, such as a printer or microfilm recorder, that produces
21 non-volatile, human-readable documents. If such a device is not avail‐
22 able to the application, or if the system provides no such device, the
23 lp utility shall exit with a non-zero exit status.
24 The actual writing to the output device may occur some time after the
26 lp utility successfully exits. During the portion of the writing that
27 corresponds to each input file, the implementation shall guarantee
28 exclusive access to the device.
29 The lp utility shall associate a unique request ID with each request.
31 Normally, a banner page is produced to separate and identify each print
33 job. This page may be suppressed by implementation-defined conditions,
34 such as an operator command or one of the -o option values.
35
37 The lp utility shall conform to the Base Definitions volume of
38 POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines.
39 The following options shall be supported:
41 -c Exit only after further access to any of the input files is
43 no longer required. The application can then safely delete or
44 modify the files without affecting the output operation. Nor‐
45 mally, files are not copied, but are linked whenever possi‐
46 ble. If the -c option is not given, then the user should be
47 careful not to remove any of the files before the request has
48 been printed in its entirety. It should also be noted that in
49 the absence of the -c option, any changes made to the named
50 files after the request is made but before it is printed may
51 be reflected in the printed output. On some implementations,
52 -c may be on by default.
53 -d dest Specify a string that names the destination (dest). If dest
55 is a printer, the request shall be printed only on that spe‐
56 cific printer. If dest is a class of printers, the request
57 shall be printed on the first available printer that is a
58 member of the class. Under certain conditions (printer
59 unavailability, file space limitation, and so on), requests
60 for specific destinations need not be accepted. Destination
61 names vary between systems.
62 If -d is not specified, and neither the LPDEST nor PRINTER
64 environment variable is set, an unspecified destination is
65 used. The -d dest option shall take precedence over LPDEST,
66 which in turn shall take precedence over PRINTER. Results
67 are undefined when dest contains a value that is not a valid
68 destination name.
69 -m Send mail (see mailx) after the files have been printed. By
71 default, no mail is sent upon normal completion of the print
72 request.
73 -n copies Write copies number of copies of the files, where copies is a
75 positive decimal integer. The methods for producing multiple
76 copies and for arranging the multiple copies when multiple
77 file operands are used are unspecified, except that each file
78 shall be output as an integral whole, not interleaved with
79 portions of other files.
80 -o option Specify printer-dependent or class-dependent options. Sev‐
82 eral such options may be collected by specifying the -o
83 option more than once.
84 -s Suppress messages from lp.
86 -t title Write title on the banner page of the output.
88 -w Write a message on the user's terminal after the files have
90 been printed. If the user is not logged in, then mail shall
91 be sent instead.
92
94 The following operand shall be supported:
95 file A pathname of a file to be output. If no file operands are
97 specified, or if a file operand is '-', the standard input
98 shall be used. If a file operand is used, but the -c option
99 is not specified, the process performing the writing to the
100 output device may have user and group permissions that differ
101 from that of the process invoking lp.
102
104 The standard input shall be used only if no file operands are speci‐
105 fied, or if a file operand is '-'. See the INPUT FILES section.
106
108 The input files shall be text files.
109
111 The following environment variables shall affect the execution of lp:
112 LANG Provide a default value for the internationalization vari‐
114 ables that are unset or null. (See the Base Definitions vol‐
115 ume of POSIX.1‐2017, Section 8.2, Internationalization Vari‐
116 ables for the precedence of internationalization variables
117 used to determine the values of locale categories.)
118 LC_ALL If set to a non-empty string value, override the values of
120 all the other internationalization variables.
121 LC_CTYPE Determine the locale for the interpretation of sequences of
123 bytes of text data as characters (for example, single-byte as
124 opposed to multi-byte characters in arguments and input
125 files).
126 LC_MESSAGES
128 Determine the locale that should be used to affect the format
129 and contents of diagnostic messages written to standard error
130 and informative messages written to standard output.
131 LC_TIME Determine the format and contents of date and time strings
133 displayed in the lp banner page, if any.
134 LPDEST Determine the destination. If the LPDEST environment variable
136 is not set, the PRINTER environment variable shall be used.
137 The -d dest option takes precedence over LPDEST. Results are
138 undefined when -d is not specified and LPDEST contains a
139 value that is not a valid destination name.
140 NLSPATH Determine the location of message catalogs for the processing
142 of LC_MESSAGES.
143 PRINTER Determine the output device or destination. If the LPDEST and
145 PRINTER environment variables are not set, an unspecified
146 output device is used. The -d dest option and the LPDEST
147 environment variable shall take precedence over PRINTER.
148 Results are undefined when -d is not specified, LPDEST is
149 unset, and PRINTER contains a value that is not a valid
150 device or destination name.
151 TZ Determine the timezone used to calculate date and time
153 strings displayed in the lp banner page, if any. If TZ is
154 unset or null, an unspecified default timezone shall be used.
155
157 Default.
158
160 The lp utility shall write a request ID to the standard output, unless
161 -s is specified. The format of the message is unspecified. The request
162 ID can be used on systems supporting the historical cancel and lpstat
163 utilities.
164
166 The standard error shall be used only for diagnostic messages.
167
169 None.
170
172 None.
173
175 The following exit values shall be returned:
176 0 All input files were processed successfully.
178 >0 No output device was available, or an error occurred.
180
182 Default.
183 The following sections are informative.
185
187 The pr and fold utilities can be used to achieve reasonable formatting
188 for the implementation's default page size.
189 A conforming application can use one of the file operands only with the
191 -c option or if the file is publicly readable and guaranteed to be
192 available at the time of printing. This is because POSIX.1‐2008 gives
193 the implementation the freedom to queue up the request for printing at
194 some later time by a different process that might not be able to access
195 the file.
196
198 1. To print file file:
199 lp -c file
202 2. To print multiple files with headers:
204 pr file1 file2 | lp
207
209 The lp utility was designed to be a basic version of a utility that is
210 already available in many historical implementations. The standard
211 developers considered that it should be implementable simply as:
212 cat "$@" > /dev/lp
215 after appropriate processing of options, if that is how the implementa‐
217 tion chose to do it and if exclusive access could be granted (so that
218 two users did not write to the device simultaneously). Although in the
219 future the standard developers may add other options to this utility,
220 it should always be able to execute with no options or operands and
221 send the standard input to an unspecified output device.
222 This volume of POSIX.1‐2017 makes no representations concerning the
224 format of the printed output, except that it must be ``human-readable''
225 and ``non-volatile''. Thus, writing by default to a disk or tape drive
226 or a display terminal would not qualify. (Such destinations are not
227 prohibited when -d dest, LPDEST, or PRINTER are used, however.)
228 This volume of POSIX.1‐2017 is worded such that a ``print job'' con‐
230 sisting of multiple input files, possibly in multiple copies, is guar‐
231 anteed to print so that any one file is not intermixed with another,
232 but there is no statement that all the files or copies have to print
233 out together.
234 The -c option may imply a spooling operation, but this is not required.
236 The utility can be implemented to wait until the printer is ready and
237 then wait until it is finished. Because of that, there is no attempt to
238 define a queuing mechanism (priorities, classes of output, and so on).
239 On some historical systems, the request ID reported on the STDOUT can
241 be used to later cancel or find the status of a request using utilities
242 not defined in this volume of POSIX.1‐2017.
243 Although the historical System V lp and BSD lpr utilities have provided
245 similar functionality, they used different names for the environment
246 variable specifying the destination printer. Since the name of the
247 utility here is lp, LPDEST (used by the System V lp utility) was given
248 precedence over PRINTER (used by the BSD lpr utility). Since environ‐
249 ments of users frequently contain one or the other environment vari‐
250 able, the lp utility is required to recognize both. If this was not
251 done, many applications would send output to unexpected output devices
252 when users moved from system to system.
253 Some have commented that lp has far too little functionality to make it
255 worthwhile. Requests have proposed additional options or operands or
256 both that added functionality. The requests included:
257 * Wording requiring the output to be ``hardcopy''
259 * A requirement for multiple printers
261 * Options for supporting various page-description languages
263 Given that a compliant system is not required to even have a printer,
265 placing further restrictions upon the behavior of the printer is not
266 useful. Since hardcopy format is so application-dependent, it is diffi‐
267 cult, if not impossible, to select a reasonable subset of functionality
268 that should be required on all compliant systems.
269 The term unspecified is used in this section in lieu of implementation-
271 defined as most known implementations would not be able to make defini‐
272 tive statements in their conformance documents; the existence and usage
273 of printers is very dependent on how the system administrator config‐
274 ures each individual system.
275 Since the default destination, device type, queuing mechanisms, and
277 acceptable forms of input are all unspecified, usage guidelines for
278 what a conforming application can do are as follows:
279 * Use the command in a pipeline, or with -c, so that there are no
281 permission problems and the files can be safely deleted or modi‐
282 fied.
283 * Limit output to text files of reasonable line lengths and printable
285 characters and include no device-specific formatting information,
286 such as a page description language. The meaning of ``reasonable''
287 in this context can only be answered as a quality-of-implementation
288 issue, but it should be apparent from historical usage patterns in
289 the industry and the locale. The pr and fold utilities can be used
290 to achieve reasonable formatting for the default page size of the
291 implementation.
292 Alternatively, the application can arrange its installation in such a
294 way that it requires the system administrator or operator to provide
295 the appropriate information on lp options and environment variable val‐
296 ues.
297 At a minimum, having this utility in this volume of POSIX.1‐2017 tells
299 the industry that conforming applications require a means to print out‐
300 put and provides at least a command name and LPDEST routing mechanism
301 that can be used for discussions between vendors, application develop‐
302 ers, and users. The use of ``should'' in the DESCRIPTION of lp clearly
303 shows the intent of the standard developers, even if they cannot man‐
304 date that all systems (such as laptops) have printers.
305 This volume of POSIX.1‐2017 does not specify what the ownership of the
307 process performing the writing to the output device may be. If -c is
308 not used, it is unspecified whether the process performing the writing
309 to the output device has permission to read file if there are any
310 restrictions in place on who may read file until after it is printed.
311 Also, if -c is not used, the results of deleting file before it is
312 printed are unspecified.
313
315 None.
316
318 mailx
319 The Base Definitions volume of POSIX.1‐2017, Chapter 8, Environment
321 Variables, Section 12.2, Utility Syntax Guidelines
322
324 Portions of this text are reprinted and reproduced in electronic form
325 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
326 table Operating System Interface (POSIX), The Open Group Base Specifi‐
327 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
328 Electrical and Electronics Engineers, Inc and The Open Group. In the
329 event of any discrepancy between this version and the original IEEE and
330 The Open Group Standard, the original IEEE and The Open Group Standard
331 is the referee document. The original Standard can be obtained online
332 at http://www.opengroup.org/unix/online.html .
333 Any typographical or formatting errors that appear in this page are
335 most likely to have been introduced during the conversion of the source
336 files to man page format. To report such errors, see https://www.ker‐
337 nel.org/doc/man-pages/reporting_bugs.html .
338IEEE/The Open Group 2017 LP(1P)