FMT(1) BSD 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 hyphenated.
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 white-
space 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.)
Treat the chars (and no others) as sentence-ending characters. By default the sen-
tence-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.
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.
Assume that the input files' tabs assume number spaces per tab stop. The default is
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))
will reformat a paragraph, evening the lines.
The fmt command appeared in 3BSD.
The version described herein is a complete rewrite and appeared in FreeBSD 4.4.
Liz Allen (added goal length concept)
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
BSD June 25, 2000 BSD