Manual Pages  — FOLD

fold – fold long lines for finite width output device

SYNOPSIS DESCRIPTION ENVIRONMENT EXAMPLES SEE ALSO STANDARDS HISTORY AUTHORS BUGS

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

The fold utility is a filter which folds the contents of the specified files, or the standard input if no files are specified, breaking the lines to have a maximum of 80 columns.

The options are as follows:

-b
	Count width in bytes rather than column positions.
-s
	Fold line after the last blank character within the first width column positions (or bytes).
-w width
	Specify a line width to use instead of the default 80 columns. The width value should be a multiple of 8 if tabs are present, or the tabs should be expanded using expand(1) before using fold.

Fold text in standard input with a width of 20 columns:

$ echo "I am smart enough to know that I am dumb" | fold -w 15
I am smart enou
gh to know that
 I am dumb

Same as above but breaking lines after the last blank character:

$ echo "I am smart enough to know that I am dumb" | fold -s -w 15
I am smart
enough to know
that I am dumb

The fold utility conforms to IEEE Std 1003.1-2001 ("POSIX.1").

The fold utility first appeared in BSD 1 . It was rewritten for BSD 4.3 Reno to improve speed and modernize style. The -b and -s options were added to NetBSD for IEEE Std 1003.2 ("POSIX.2") compliance.

Bill Joy wrote the original version of fold on June 28, 1977. Kevin Ruddy rewrote the command in 1990, and J. T. Conklin added the missing options in 1993.