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fold(1)


NAME

  fold - Breaks or wraps lines in a file


SYNOPSIS

  fold [-bs] [-w width | -width] [file...]

  The fold command wraps lines in the specified files.	If a file is not
  specified, standard input is the default. All lines are wrapped to meet the
  maximum width specified.


STANDARDS

  Interfaces documented on this reference page conform to industry standards
  as follows:

  fold:	 XCU5.0

  Refer to the standards(5) reference page for more information about
  industry standards and associated tags.


OPTIONS

  -b  Specifies that width be counted in bytes rather than in column
      positions.  Using the -b option does not limit lines to LINE_MAX bytes.

  -s  Breaks (or wraps) a line if a segment of the line contains a blank
      character in the first width column position (or bytes).	This enables
      the line to meet width constraints.  If a blank character is not in the
      correct width column position, the -s option has no affect on that
      input line.

  -w width or -width
      Specifies the maximum width to use when lines are wrapped in column
      positions (or bytes if the -b option is specified).  Either -w width or
      -width is acceptable input where width is the number of column
      positions (or bytes).  The default value is 80.


DESCRIPTION

  The fold command is a filter that wraps lines from the specified input
  files or standard input to a maximum of width (or bytes, if the -b option
  is specified).  The fold command wraps lines by inserting a newline
  character into the output so that each output line is the maximum column
  positions or bytes specified.	 A line cannot be broken in the middle of a
  character.

  The fold command is often used to send text files to line printers that
  truncate, rather than wrap, lines wider than the printer is able to print
  (usually 80 or 132 column positions).

  If the <backspace>, <tab>, or <carriage return> characters are encountered
  in the input, and the -b option is not specified, these characters are
  treated specially:

  <backspace>
      The current count of line width is decremented by one, although the
      count never becomes negative.  The fold command does not insert a
      newline character immediately before or after any backspace character.

  <tab>
      Each tab character encountered advances the column position pointer to
      the position of the next tab stop.  Tab stops are at each column
      position number, such that number modulo 8 equals 1.

  <carriage-return>
      The current count of the line width is set to zero (0).  The fold
      command does not insert a newline immediately before or after any
      carriage return.

  [Tru64 UNIX]	The fold command possibly affects underlining in a file.


EXIT STATUS

  The fold command returns the following values:

  0   All input files were successfully processed.

  1   [Tru64 UNIX]  A usage error occurred.

  2   [Tru64 UNIX]  An input file cannot be opened.  The fold command
      continues processing the other input files specified on the command
      line.


EXAMPLES

  The fold command can be used to prepare files to be joined side-by-side
  with the paste command.  For example, the contents of two files, az and AZ
  follows:

       aaaa bbbb cccc dddd eeee ffff gggg hhhh iiii jjjj kkkk llll mmmm
       nnnn oooo pppp qqqq rrrr ssss tttt uuuu vvvv wwww xxxx yyyy zzzz

       AAAA BBBB CCCC DDDD EEEE FFFF GGGG HHHH IIII JJJJ KKKK LLLL MMMM
       NNNN OOOO PPPP QQQQ RRRR SSSS TTTT UUUU VVVV WWWW XXXX YYYY ZZZZ

  To display the az and AZ files side-by-side, use the following command
  line:

       fold -w 32 az > az2; fold -w 32 AZ > AZ2; paste -d" " az2 AZ2

  Executing the previous command line results in the following output:

       aaaa bbbb cccc dddd eeee ffff gg AAAA BBBB CCCC DDDD EEEE FFFF GG
       gg hhhh iiii jjjj kkkk llll mmmm GG HHHH IIII JJJJ KKKK LLLL MMMM
       nnnn oooo pppp qqqq rrrr ssss tt NNNN OOOO PPPP QQQQ RRRR SSSS TT
       tt uuuu vvvv wwww xxxx yyyy zzzz TT UUUU VVVV WWWW XXXX YYYY ZZZZ


ENVIRONMENT VARIABLES

  The following environment variables affect the execution of fold:

  LANG
      Provides a default value for the internationalization variables that
      are unset or null. If LANG is unset or null, the corresponding value
      from the default locale is used.	If any of the internationalization
      variables contain an invalid setting, the utility behaves as if none of
      the variables had been defined.

  LC_ALL
      If set to a non-empty string value, overrides the values of all the
      other internationalization variables.

  LC_CTYPE
      Determines the locale for the interpretation of sequences of bytes of
      text data as characters (for example, single-byte as opposed to
      multibyte characters in arguments) and for the determination of the
      width in column positions each character would occupy on a constant-
      width font output device.

  LC_MESSAGES
      Determines the locale for the format and contents of diagnostic
      messages written to standard error.

  NLSPATH
      Determines the location of message catalogues for the processing of
      LC_MESSAGES.


SEE ALSO

  Commands:  cut(1), expand(1), paste(1)

  Standards:  standards(5)

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