FMT(1)                       General Commands Manual                      FMT(1)

     fmt – simple text formatter

     fmt [-cmnps] [-d chars] [-l num] [-t num]
         [goal [maximum] | -width | -w width] [file ...]

     The fmt utility is a simple text formatter which reads the concatenation of
     input files (or standard input if none are given) and produces on standard
     output a version of its input with lines as close to the goal length as
     possible without exceeding the maximum.  The goal length defaults to 65 and
     the maximum to 10 more than the goal length.  Alternatively, a single width
     parameter can be specified either by prepending a hyphen to it or by using
     -w.  For example, “fmt -w 72”, “fmt -72”, and “fmt 72 72” all produce
     identical output.  The spacing at the beginning of the input lines is
     preserved in the output, as are blank lines and interword spacing.  Lines
     are joined or split only at white space; that is, words are never joined or

     The options are as follows:

     -c      Center the text, line by line.  In this case, most of the other
             options are ignored; no splitting or joining of lines is done.

     -m      Try to format mail header lines contained in the input sensibly.

     -n      Format lines beginning with a ‘.’ (dot) character.  Normally, fmt
             does not fill these lines, for compatibility with nroff(1).

     -p      Allow indented paragraphs.  Without the -p flag, any change in the
             amount of whitespace at the start of a line results in a new
             paragraph being begun.

     -s      Collapse whitespace inside lines, so that multiple whitespace
             characters are turned into a single space.  (Or, at the end of a
             sentence, a double space.)

     -d chars
             Treat the chars (and no others) as sentence-ending characters.  By
             default the sentence-ending characters are full stop (‘.’),
             question mark (‘?’) and exclamation mark (‘!’).  Remember that some
             characters may need to be escaped to protect them from your shell.

     -l number
             Replace multiple spaces with tabs at the start of each output line,
             if possible.  Each number spaces will be replaced with one tab.
             The default is 8.  If number is 0, spaces are preserved.

     -t number
             Assume that the input files' tabs assume number spaces per tab
             stop.  The default is 8.

     The fmt utility is meant to format mail messages prior to sending, but may
     also be useful for other simple tasks.  For instance, within visual mode of
     the ex(1) editor (e.g., vi(1)) the command


     will reformat a paragraph, evening the lines.

     The LANG, LC_ALL and LC_CTYPE environment variables affect the execution of
     fmt as described in environ(7).

     fold(1), mail(1), nroff(1)

     The fmt command appeared in 3BSD.

     The version described herein is a complete rewrite and appeared in
     FreeBSD 4.4.

     Kurt Shoens
     Liz Allen (added goal length concept)
     Gareth McCaughan

     The program was designed to be simple and fast - for more complex
     operations, the standard text processors are likely to be more appropriate.

     When the first line of an indented paragraph is very long (more than about
     twice the goal length), the indentation in the output can be wrong.

     The fmt utility is not infallible in guessing what lines are mail headers
     and what lines are not.

macOS 12.1                       August 2, 2004                       macOS 12.1