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



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may dif-
       fer (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  IEEE Std 1003.1-2001,  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-sepa-
       rated 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 repre-
       sents 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 stan-
              dard 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 IEEE Std 1003.1-2001, Section 8.2, Internationalization Variables for  the  prece-
              dence 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  exam-
              ple, 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 writ-
              ten 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  fol-
       lowing):


              "%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
       Earlier versions of the cut utility worked in an environment where bytes and characters were considered equiva-
       lent (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  <new-
       line> 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:


              <user ID>:<home directory>

       Most utilities in this volume of IEEE Std 1003.1-2001 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>s 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>s or <tab>s 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
       IEEE Std 1003.1-2001, 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 Utility Description Defaults .

       The OPTIONS section was changed in response to IEEE PASC Interpretation 1003.2 #149. The change represents his-
       torical 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.

SEE ALSO
       grep, paste, Parameters and Variables

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Stan-
       dard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base  Specifica-
       tions  Issue  6,  Copyright (C) 2001-2003 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 Stan-
       dard,  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 .



IEEE/The Open Group                  2003                              CUT(1P)