The
command has been used to reformat email messages after composition and before delivery. Its syntax is similar among various Unixes, but not identical. attempts to break, fill, and join input lines to produce globally optimal, balanced output with the lengths of each line approaching the target width as closely as possible, rather than wrapping the input lines exactly as fold (Unix)| (from
BSD and
GNU Core Utilities) does. In most implementations of , the
word wrap optimization procedure usually requires two criteria: the target output line width and the maximum acceptable line width (which should be larger than the previous one to give room for optimization). It might not always be possible to give these two options simultaneously. For example, early versions of
GNU can only accept the maximum width option, which is given by the switch, or directly as the first command line option for compatibility (later versions use to specify the goal width and for the maximum width). See the
Solaris man page for and
FreeBSD manual entry for for detailed examples, and compare with the latest documentation of the GNU utility included by most
Linux distributions. See also the
Plan 9 man page. Unlike Par (command)|, has no Unicode support and does not support text justification. The command is available as a separate package for
Microsoft Windows as part of the
UnxUtils collection of
native Win32 ports of common GNU Unix-like utilities. ==Example==