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       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

       cut — cut out selected fields of each line of a file

SYNOPSIS

       cut −b list [−n] [file...]

       cut −c list [file...]

       cut −f list [−d delim] [−s] [file...]

DESCRIPTION

       The  cut  utility  shall cut out bytes (−b option), characters (−c option), or character-delimited fields
       (−f option) from each line in one or more files, concatenate them, and write them to standard output.

OPTIONS

The cut utility shall conform to the Base Definitions volume of POSIX.1‐2008, Section 12.2, Utility
Syntax Guidelines.

The application shall ensure that the option-argument list (see options −b, −c, and −f below) is a
<comma>-separated list or <blank>-separated list of positive numbers and ranges. Ranges can be in three
forms. The first is two positive numbers separated by a <hyphen> (low−high), which represents all fields
from the first number to the second number. The second is a positive number preceded by a <hyphen>
(−high), which represents all fields from field number 1 to that number. The third is a positive number
followed by a <hyphen> (low−), which represents that number to the last field, inclusive. The elements in
list can be repeated, can overlap, and can be specified in any order, but the bytes, characters, or
fields selected shall be written in the order of the input data. If an element appears in the selection
list more than once, it shall be written exactly once.

The following options shall be supported:

−b list Cut based on a list of bytes. Each selected byte shall be output unless the −n option is also
specified. It shall not be an error to select bytes not present in the input line.

−c list Cut based on a list of characters. Each selected character shall be output. It shall not be an
error to select characters not present in the input line.

−d delim Set the field delimiter to the character delim. The default is the <tab>.

−f list Cut based on a list of fields, assumed to be separated in the file by a delimiter character
(see −d). Each selected field shall be output. Output fields shall be separated by a single
occurrence of the field delimiter character. Lines with no field delimiters shall be passed
through intact, unless −s is specified. It shall not be an error to select fields not present
in the input line.

−n Do not split characters. When specified with the −b option, each element in list of the form
low−high (<hyphen>-separated numbers) shall be modified as follows:

* If the byte selected by low is not the first byte of a character, low shall be decremented
to select the first byte of the character originally selected by low. If the byte selected
by high is not the last byte of a character, high shall be decremented to select the last
byte of the character prior to the character originally selected by high, or zero if there
is no prior character. If the resulting range element has high equal to zero or low greater
than high, the list element shall be dropped from list for that input line without causing
an error.

Each element in list of the form low− shall be treated as above with high set to the number of
bytes in the current line, not including the terminating <newline>. Each element in list of
the form −high shall be treated as above with low set to 1. Each element in list of the form
num (a single number) shall be treated as above with low set to num and high set to num.

−s Suppress lines with no delimiter characters, when used with the −f option. Unless specified,
lines with no delimiters shall be passed through untouched.

OPERANDS

       The following operand shall be supported:

       file      A pathname of an input file. 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, except that line lengths shall be unlimited.

ENVIRONMENT VARIABLES

       The following environment variables shall affect the execution of cut:

       LANG      Provide a default value for the internationalization variables that are unset or null. (See the
                 Base  Definitions  volume  of POSIX.1‐2008, 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).

       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

       The cut utility output shall be a concatenation of the selected bytes, characters, or fields (one of  the
       following):

           "%s\n", <concatenation of bytes>

           "%s\n", <concatenation of characters>

           "%s\n", <concatenation of fields and field delimiters>

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    All input files were output successfully.

       >0    An error occurred.

CONSEQUENCES OF ERRORS

       Default.

       The following sections are informative.

APPLICATION USAGE

       The cut and fold utilities can be used to create text files out of files with arbitrary line lengths. The
       cut utility should be used when the number of lines (or records)  needs  to  remain  constant.  The  fold
       utility should be used when the contents of long lines need to be kept contiguous.

       Earlier  versions  of the cut utility worked in an environment where bytes and characters were considered
       equivalent (modulo <backspace> and <tab> processing in some implementations). In the  extended  world  of
       multi-byte  characters,  the  new  −b option has been added. The −n option (used with −b) allows it to be
       used to act on bytes rounded to character boundaries.  The algorithm specified for −n guarantees that:

           cut −b 1−500 −n file > file1
           cut −b 501− −n file > file2

       ends up with all the characters in file appearing exactly once in file1 or file2.  (There is, however,  a
       <newline> in both file1 and file2 for each <newline> in file.)

EXAMPLES

Examples of the option qualifier list:

1,4,7 Select the first, fourth, and seventh bytes, characters, or fields and field delimiters.

1−3,8 Equivalent to 1,2,3,8.

−5,10 Equivalent to 1,2,3,4,5,10.

3− Equivalent to third to last, inclusive.

The low−high forms are not always equivalent when used with −b and −n and multi-byte characters; see the
description of −n.

The following command:

cut −d : −f 1,6 /etc/passwd

reads the System V password file (user database) and produces lines of the form:

Most utilities in this volume of POSIX.1‐2008 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

RATIONALE

Some historical implementations do not count <backspace> characters in determining character counts with
the −c option. This may be useful for using cut for processing nroff output. It was deliberately decided
not to have the −c option treat either <backspace> or <tab> characters in any special fashion. The fold
utility does treat these characters specially.

Unlike other utilities, some historical implementations of cut exit after not finding an input file,
rather than continuing to process the remaining file operands. This behavior is prohibited by this volume
of POSIX.1‐2008, where only the exit status is affected by this problem.

The behavior of cut when provided with either mutually-exclusive options or options that do not work
logically together has been deliberately left unspecified in favor of global wording in Section 1.4,
Utility Description Defaults.

The OPTIONS section was changed in response to IEEE PASC Interpretation 1003.2 #149. The change
represents historical practice on all known systems. The original standard was ambiguous on the nature of
the output.

The list option-arguments are historically used to select the portions of the line to be written, but do
not affect the order of the data. For example:

echo abcdefghi | cut −c6,2,4−7,1

yields "abdefg".

A proposal to enhance cut with the following option:

−o Preserve the selected field order. When this option is specified, each byte, character, or field
(or ranges of such) shall be written in the order specified by the list option-argument, even if
this requires multiple outputs of the same bytes, characters, or fields.

was rejected because this type of enhancement is outside the scope of the IEEE P1003.2b draft standard.

FUTURE DIRECTIONS

       None.

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition,
       Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open  Group  Base
       Specifications  Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc
       and The Open Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/online.html .

       Any  typographical  or formatting errors that appear in this page are most likely to have been introduced
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