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PROLOG
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
pr — print files
SYNOPSIS
pr [+page] [-column] [-adFmrt] [-e[char][gap]] [-h header] [-i[char][gap]]
[-l lines] [-n[char][width]] [-o offset] [-s[char]] [-w width] [-fp]
[file...]
DESCRIPTION
The pr utility is a printing and pagination filter. If multiple input files are specified,
each shall be read, formatted, and written to standard output. By default, the input shall
be separated into 66-line pages, each with:
* A 5-line header that includes the page number, date, time, and the pathname of the
file
* A 5-line trailer consisting of blank lines
If standard output is associated with a terminal, diagnostic messages shall be deferred
until the pr utility has completed processing.
When options specifying multi-column output are specified, output text columns shall be of
equal width; input lines that do not fit into a text column shall be truncated. By
default, text columns shall be separated with at least one <blank>.
OPTIONS
The pr utility shall conform to the Base Definitions volume of POSIX.1‐2017, Section 12.2,
Utility Syntax Guidelines, except that: the page option has a '+' delimiter; page and
column can be multi-digit numbers; some of the option-arguments are optional; and some of
the option-arguments cannot be specified as separate arguments from the preceding option
letter. In particular, the -s option does not allow the option letter to be separated from
its argument, and the options -e, -i, and -n require that both arguments, if present, not
be separated from the option letter.
The following options shall be supported. In the following option descriptions, column,
lines, offset, page, and width are positive decimal integers; gap is a non-negative
decimal integer.
+page Begin output at page number page of the formatted input.
-column Produce multi-column output that is arranged in column columns (the default
shall be 1) and is written down each column in the order in which the text is
received from the input file. This option should not be used with -m. The
options -e and -i shall be assumed for multiple text-column output. Whether or
not text columns are produced with identical vertical lengths is unspecified,
but a text column shall never exceed the length of the page (see the -l option).
When used with -t, use the minimum number of lines to write the output.
-a Modify the effect of the -column option so that the columns are filled across
the page in a round-robin order (for example, when column is 2, the first input
line heads column 1, the second heads column 2, the third is the second line in
column 1, and so on).
-d Produce output that is double-spaced; append an extra <newline> following every
<newline> found in the input.
-e[char][gap]
Expand each input <tab> to the next greater column position specified by the
formula n*gap+1, where n is an integer > 0. If gap is zero or is omitted, it
shall default to 8. All <tab> characters in the input shall be expanded into the
appropriate number of <space> characters. If any non-digit character, char, is
specified, it shall be used as the input <tab>. If the first character of the
-e option-argument is a digit, the entire option-argument shall be assumed to be
gap.
-f Use a <form-feed> for new pages, instead of the default behavior that uses a
sequence of <newline> characters. Pause before beginning the first page if the
standard output is associated with a terminal.
-F Use a <form-feed> for new pages, instead of the default behavior that uses a
sequence of <newline> characters.
-h header Use the string header to replace the contents of the file operand in the page
header.
-i[char][gap]
In output, replace <space> characters with <tab> characters wherever one or more
adjacent <space> characters reach column positions gap+1, 2* gap+1, 3* gap+1,
and so on. If gap is zero or is omitted, default tab settings at every eighth
column position shall be assumed. If any non-digit character, char, is
specified, it shall be used as the output <tab>. If the first character of the
-i option-argument is a digit, the entire option-argument shall be assumed to be
gap.
-l lines Override the 66-line default and reset the page length to lines. If lines is
not greater than the sum of both the header and trailer depths (in lines), the
pr utility shall suppress both the header and trailer, as if the -t option were
in effect.
-m Merge files. Standard output shall be formatted so the pr utility writes one
line from each file specified by a file operand, side by side into text columns
of equal fixed widths, in terms of the number of column positions.
Implementations shall support merging of at least nine file operands.
-n[char][width]
Provide width-digit line numbering (default for width shall be 5). The number
shall occupy the first width column positions of each text column of default
output or each line of -m output. If char (any non-digit character) is given, it
shall be appended to the line number to separate it from whatever follows
(default for char is a <tab>).
-o offset Each line of output shall be preceded by offset <space> characters. If the -o
option is not specified, the default offset shall be zero. The space taken is in
addition to the output line width (see the -w option below).
-p Pause before beginning each page if the standard output is directed to a
terminal (pr shall write an <alert> to standard error and wait for a <carriage-
return> to be read on /dev/tty).
-r Write no diagnostic reports on failure to open files.
-s[char] Separate text columns by the single character char instead of by the appropriate
number of <space> characters (default for char shall be <tab>).
-t Write neither the five-line identifying header nor the five-line trailer usually
supplied for each page. Quit writing after the last line of each file without
spacing to the end of the page.
-w width Set the width of the line to width column positions for multiple text-column
output only. If the -w option is not specified and the -s option is not
specified, the default width shall be 72. If the -w option is not specified and
the -s option is specified, the default width shall be 512.
For single column output, input lines shall not be truncated.
OPERANDS
The following operand shall be supported:
file A pathname of a file to be written. If no file operands are specified, or if a
file operand is '-', the standard input shall be used.
STDIN
The standard input shall be used only if no file operands are specified, or if a file
operand is '-'. See the INPUT FILES section.
INPUT FILES
The input files shall be text files.
The file /dev/tty shall be used to read responses required by the -p option.
ENVIRONMENT VARIABLES
The following environment variables shall affect the execution of pr:
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 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) and which characters are defined as printable
(character class print). Non-printable characters are still written to standard
output, but are not counted for the purpose for column-width and line-length
calculations.
LC_MESSAGES
Determine the locale that should be used to affect the format and contents of
diagnostic messages written to standard error.
LC_TIME Determine the format of the date and time for use in writing header lines.
NLSPATH Determine the location of message catalogs for the processing of LC_MESSAGES.
TZ Determine the timezone used to calculate date and time strings written in header
lines. If TZ is unset or null, an unspecified default timezone shall be used.
ASYNCHRONOUS EVENTS
If pr receives an interrupt while writing to a terminal, it shall flush all accumulated
error messages to the screen before terminating.
STDOUT
The pr utility output shall be a paginated version of the original file (or files). This
pagination shall be accomplished using either <form-feed> characters or a sequence of
<newline> characters, as controlled by the -F or -f option. Page headers shall be
generated unless the -t option is specified. The page headers shall be of the form:
"\n\n%s %s Page %d\n\n\n", <output of date>, <file>, <page number>
In the POSIX locale, the <output of date> field, representing the date and time of last
modification of the input file (or the current date and time if the input file is standard
input), shall be equivalent to the output of the following command as it would appear if
executed at the given time:
date "+%b %e %H:%M %Y"
without the trailing <newline>, if the page being written is from standard input. If the
page being written is not from standard input, in the POSIX locale, the same format shall
be used, but the time used shall be the modification time of the file corresponding to
file instead of the current time. When the LC_TIME locale category is not set to the POSIX
locale, a different format and order of presentation of this field may be used.
If the standard input is used instead of a file operand, the <file> field shall be
replaced by a null string.
If the -h option is specified, the <file> field shall be replaced by the header argument.
STDERR
The standard error shall be used for diagnostic messages and for alerting the terminal
when -p is specified.
OUTPUT FILES
None.
EXTENDED DESCRIPTION
None.
EXIT STATUS
The following exit values shall be returned:
0 Successful completion.
>0 An error occurred.
CONSEQUENCES OF ERRORS
Default.
The following sections are informative.
APPLICATION USAGE
A conforming application must protect its first operand, if it starts with a <plus-sign>,
by preceding it with the "--" argument that denotes the end of the options. For example,
pr+x could be interpreted as an invalid page number or a file operand.
EXAMPLES
1. Print a numbered list of all files in the current directory:
ls -a | pr -n -h "Files in $(pwd)."
2. Print file1 and file2 as a double-spaced, three-column listing headed by ``file
list'':
pr -3d -h "file list" file1 file2
3. Write file1 on file2, expanding tabs to columns 10, 19, 28, ...:
pr -e9 -t <file1 >file2
RATIONALE
This utility is one of those that does not follow the Utility Syntax Guidelines because of
its historical origins. The standard developers could have added new options that obeyed
the guidelines (and marked the old options obsolescent) or devised an entirely new
utility; there are examples of both actions in this volume of POSIX.1‐2017. Because of its
widespread use by historical applications, the standard developers decided to exempt this
version of pr from many of the guidelines.
Implementations are required to accept option-arguments to the -h, -l, -o, and -w options
whether presented as part of the same argument or as a separate argument to pr, as
suggested by the Utility Syntax Guidelines. The -n and -s options, however, are specified
as in historical practice because they are frequently specified without their optional
arguments. If a <blank> were allowed before the option-argument in these cases, a file
operand could mistakenly be interpreted as an option-argument in historical applications.
The text about the minimum number of lines in multi-column output was included to ensure
that a best effort is made in balancing the length of the columns. There are known
historical implementations in which, for example, 60-line files are listed by pr -2 as one
column of 56 lines and a second of 4. Although this is not a problem when a full page with
headers and trailers is produced, it would be relatively useless when used with -t.
Historical implementations of the pr utility have differed in the action taken for the -f
option. BSD uses it as described here for the -F option; System V uses it to change
trailing <newline> characters on each page to a <form-feed> and, if standard output is a
TTY device, sends an <alert> to standard error and reads a line from /dev/tty before the
first page. There were strong arguments from both sides of this issue concerning
historical practice and as a result the -F option was added. XSI-conformant systems
support the System V historical actions for the -f option.
The <output of date> field in the -l format is specified only for the POSIX locale. As
noted, the format can be different in other locales. No mechanism for defining this is
present in this volume of POSIX.1‐2017, as the appropriate vehicle is a message catalog;
that is, the format should be specified as a ``message''.
FUTURE DIRECTIONS
None.
SEE ALSO
expand, lp
The Base Definitions volume of POSIX.1‐2017, Chapter 8, Environment Variables, Section
12.2, Utility Syntax Guidelines
COPYRIGHT
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 .