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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

       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>  (lowhigh),  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 lowhigh (<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  lowhigh  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 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.

SEE ALSO

       Section 2.5, Parameters and Variables, fold, grep, paste

       The Base Definitions volume of POSIX.1‐2008, 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, 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  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 .