FMT (1) | General commands | Unix Manual Pages | :man▋
fmt - simple text formatter
fmt [-cmnps] [-d chars] [-l num] [-t num] [goal[maximum| width |-w width]] 
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 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)
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