fold - filter for folding lines
fold [-bs] [-w width | -width] [file...]
The fold utility is a filter that will fold lines from its
input files, breaking the lines to have a maximum of width
column positions (or bytes, if the -b option is specified).
Lines will be broken by the insertion of a NEWLINE character
such that each output line (referred to later in this sec-
tion as a segment) is the maximum width possible that does
not exceed the specified number of column positions (or
bytes). A line will not be broken in the middle of a charac-
ter. The behavior is undefined if width is less than the
number of columns any single character in the input would
If the CARRIAGE-RETURN, BACKSPACE, or TAB characters are
encountered in the input, and the -b option is not speci-
fied, they will be treated specially:
The current count of line width will be decremented by
one, although the count never will become negative.
fold will not insert a NEWLINE character immediately
before or after any BACKSPACE character.
The current count of line width will be set to 0. fold
will not insert a NEWLINE character immediately before
or after any CARRIAGE-RETURN character.
TAB Each TAB character encountered will advance the column
position pointer to the next tab stop. Tab stops will
be at each column position n such that n modulo 8
The following options are supported:
-b Counts width in bytes rather than column positions.
-s If a segment of a line contains a blank character
within the first width column positions (or bytes),
breaks the line after the last such blank character
meeting the width constraints. If there is no blank
character meeting the requirements, the -s option will
have no effect for that output segment of the input
Specifies the maximum line length, in column positions
(or bytes if -b is specified). If width is not a posi-
tive decimal number, an error is returned. The default
value is 80.
The following operand is supported:
file A path name of a text file to be folded. If no file
operands are specified, the standard input will be
Example 1: Submitting a file of possibly long lines to the
An example invocation that submits a file of possibly long
lines to the line printer (under the assumption that the
user knows the line width of the printer to be assigned by
example% fold -w 132 bigfile | lp
See environ(5) for descriptions of the following environment
variables that affect the execution of fold: LANG, LC_ALL,
LC_CTYPE, LC_MESSAGES, and NLSPATH.
The following exit values are returned:
0 All input files were processed successfully.
>0 An error occurred.
See attributes(5) for descriptions of the following attri-
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
| Availability | SUNWcsu |
| CSI | enabled |
| Interface Stability | Standard |
cut(1), pr(1), attributes(5), environ(5), standards(5)
fold and cut(1) can be used to create text files out of
files with arbitrary line lengths. fold should be used when
the contents of long lines need to be kept contiguous. cut
should be used when the number of lines (or records) needs
to remain constant.
fold is frequently used to send text files to line printers
that truncate, rather than fold, lines wider than the
printer is able to print (usually 80 or 132 column posi-
fold may not work correctly if underlining is present.
Man(1) output converted with