freebsd/usr.bin/fmt/fmt.1

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.\" Modified by Gareth McCaughan to describe the new version of `fmt'
.\" rather than the old one.
.Dd October 29, 2020
.Dt FMT 1
.Os
.Sh NAME
.Nm fmt
.Nd simple text formatter
.Sh SYNOPSIS
.Nm
.Op Fl cmnps
.Op Fl d Ar chars
.Op Fl l Ar num
.Op Fl t Ar num
.Op Ar goal Oo Ar maximum Oc | Fl Ns Ar width | Fl w Ar width
.Op Ar
.Sh DESCRIPTION
The
.Nm
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
.Ar goal
length
as possible without exceeding the
.Ar maximum .
The
.Ar goal
length defaults
to 65 and the
.Ar maximum
to 10 more than the
.Ar goal
length.
Alternatively, a single
.Ar width
parameter can be specified either by prepending a hyphen to it or by using
.Fl w .
For example,
.Dq Li fmt -w 72 ,
.Dq Li fmt -72 ,
and
.Dq Li 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.
.Pp
The options are as follows:
.Bl -tag -width indent
.It Fl 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.
.It Fl m
Try to format mail header lines contained in the input sensibly.
.It Fl n
Format lines beginning with a
.Ql \&.
(dot) character.
.It Fl p
Allow indented paragraphs.
Without the
.Fl p
flag, any change in the amount of whitespace at the start of a line
results in a new paragraph being begun.
.It Fl 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.)
.It Fl d Ar chars
Treat the
.Ar chars
(and no others) as sentence-ending characters.
By default the
sentence-ending characters are full stop
.Pq Ql \&. ,
question mark
.Pq Ql \&?
and exclamation mark
.Pq Ql \&! .
Remember that some characters may need to be
escaped to protect them from your shell.
.It Fl l Ar number
Replace multiple spaces with tabs at the start of each output
line, if possible.
Each
.Ar number
spaces will be replaced with one tab.
The default is 8.
If
.Ar number
is 0, spaces are preserved.
.It Fl t Ar number
Assume that the input files' tabs assume
.Ar number
spaces per tab stop.
The default is 8.
.El
.Pp
The
.Nm
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
.Xr ex 1
editor (e.g.,
.Xr vi 1 )
the command
.Pp
.Dl \&!}fmt
.Pp
will reformat a paragraph,
evening the lines.
.Sh ENVIRONMENT
The
.Ev LANG , LC_ALL
and
.Ev LC_CTYPE
environment variables affect the execution of
.Nm
as described in
.Xr environ 7 .
.Sh EXAMPLES
Center the text in standard input:
.Bd -literal -offset indent
$ echo -e 'The merit of all things\enlies\enin their difficulty' | fmt -c
                     The merit of all things
                               lies
                       in their difficulty
.Ed
.Pp
Format the text in standard input collapsing spaces:
.Bd -literal -offset indent
$ echo -e 'Multiple   spaces    will be collapsed' | fmt -s
Multiple spaces will be collapsed
.Ed
.Sh SEE ALSO
.Xr fold 1 ,
.Xr mail 1
.Sh HISTORY
The
.Nm
command appeared in
.Bx 3 .
.Pp
The version described herein is a complete rewrite and appeared in
.Fx 4.4 .
.Sh AUTHORS
.An Kurt Shoens
.An Liz Allen
(added
.Ar goal
length concept)
.An Gareth McCaughan
.Sh BUGS
The program was designed to be simple and fast \- for more complex
operations, the standard text processors are likely to be more appropriate.
.Pp
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.
.Pp
The
.Nm
utility is not infallible in guessing what lines are mail headers and what
lines are not.