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PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface
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NAME
paste — merge corresponding or subsequent lines of files
SYNOPSIS
paste [-s] [-d list] file...
DESCRIPTION
The paste utility shall concatenate the corresponding lines of the given input files, and write the
resulting lines to standard output.
The default operation of paste shall concatenate the corresponding lines of the input files. The
<newline> of every line except the line from the last input file shall be replaced with a <tab>.
If an end-of-file condition is detected on one or more input files, but not all input files, paste shall
behave as though empty lines were read from the files on which end-of-file was detected, unless the -s
option is specified.
OPTIONS
The paste utility shall conform to the Base Definitions volume of POSIX.1‐2017, Section 12.2, Utility
Syntax Guidelines.
The following options shall be supported:
-d list Unless a <backslash> character appears in list, each character in list is an element specifying
a delimiter character. If a <backslash> character appears in list, the <backslash> character
and one or more characters following it are an element specifying a delimiter character as
described below. These elements specify one or more delimiters to use, instead of the default
<tab>, to replace the <newline> of the input lines. The elements in list shall be used
circularly; that is, when the list is exhausted the first element from the list is reused. When
the -s option is specified:
* The last <newline> in a file shall not be modified.
* The delimiter shall be reset to the first element of list after each file operand is
processed.
When the -s option is not specified:
* The <newline> characters in the file specified by the last file operand shall not be
modified.
* The delimiter shall be reset to the first element of list each time a line is processed
from each file.
If a <backslash> character appears in list, it and the character following it shall be used to
represent the following delimiter characters:
\n <newline>.
\t <tab>.
\\ <backslash> character.
\0 Empty string (not a null character). If '\0' is immediately followed by the character
'x', the character 'X', or any character defined by the LC_CTYPE digit keyword (see the
Base Definitions volume of POSIX.1‐2017, Chapter 7, Locale), the results are unspecified.
If any other characters follow the <backslash>, the results are unspecified.
-s Concatenate all of the lines from each input file into one line of output per file, in command
line order. The <newline> of every line except the last line in each input file shall be
replaced with a <tab>, unless otherwise specified by the -d option. If an input file is empty,
the output line corresponding to that file shall consist of only a <newline> character.
OPERANDS
The following operand shall be supported:
file A pathname of an input file. If '-' is specified for one or more of the files, the standard
input shall be used; the standard input shall be read one line at a time, circularly, for each
instance of '-'. Implementations shall support pasting of at least 12 file operands.
STDIN
The standard input shall be used only if one or more file operands is '-'. See the INPUT FILES section.
INPUT FILES
The input files shall be text files, except that line lengths shall be unlimited.
ENVIRONMENT VARIABLES
The following environment variables shall affect the execution of paste:
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).
LC_MESSAGES
Determine the locale that should be used to affect the format and contents of diagnostic
messages written to standard error.
NLSPATH Determine the location of message catalogs for the processing of LC_MESSAGES.
ASYNCHRONOUS EVENTS
Default.
STDOUT
Concatenated lines of input files shall be separated by the <tab> (or other characters under the control
of the -d option) and terminated by a <newline>.
STDERR
The standard error shall be used only for diagnostic messages.
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
If one or more input files cannot be opened when the -s option is not specified, a diagnostic message
shall be written to standard error, but no output is written to standard output. If the -s option is
specified, the paste utility shall provide the default behavior described in Section 1.4, Utility
Description Defaults.
The following sections are informative.
APPLICATION USAGE
When the escape sequences of the list option-argument are used in a shell script, they must be quoted;
otherwise, the shell treats the <backslash> as a special character.
Conforming applications should only use the specific <backslash>-escaped delimiters presented in this
volume of POSIX.1‐2017. Historical implementations treat '\x', where 'x' is not in this list, as 'x', but
future implementations are free to expand this list to recognize other common escapes similar to those
accepted by printf and other standard utilities.
Most of the standard utilities work on text files. The cut utility can be used to turn files with
arbitrary line lengths into a set of text files containing the same data. The paste utility can be used
to create (or recreate) files with arbitrary line lengths. For example, if file contains long lines:
cut -b 1-500 -n file > file1
cut -b 501- -n file > file2
creates file1 (a text file) with lines no longer than 500 bytes (plus the <newline>) and file2 that
contains the remainder of the data from file. Note that file2 is not a text file if there are lines in
file that are longer than 500 + {LINE_MAX} bytes. The original file can be recreated from file1 and file2
using the command:
paste -d "\0" file1 file2 > file
The commands:
paste -d "\0" ...
paste -d "" ...
are not necessarily equivalent; the latter is not specified by this volume of POSIX.1‐2017 and may result
in an error. The construct '\0' is used to mean ``no separator'' because historical versions of paste did
not follow the syntax guidelines, and the command:
paste -d"" ...
could not be handled properly by getopt().
EXAMPLES
1. Write out a directory in four columns:
ls | paste - - - -
2. Combine pairs of lines from a file into single lines:
paste -s -d "\t\n" file
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
Section 1.4, Utility Description Defaults, cut, grep, pr
The Base Definitions volume of POSIX.1‐2017, Chapter 7, Locale, 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 .
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