fmt — Simple optimal text ForMatTer
fmt reads from the specified file arguments or stdin, and writes to stdout.
$ fmt myfile — Format myfile and max line length is 75.
$ fmt f1 f2 — Format f1 f2 and max line length is 75.
$ fmt -w 60 f1 f2 — Same as above but max line length is 60.
$ fmt -s myfile — Don’t split the small line. Useful if your file contains some sample program codes.
$ fmt -u myfile — Uniform spacing. One space between words. Two space between sentences.
$ fmt -p BB myfile — Only lines beginning with BB will be formatted.
$ fmt -t myfile — Paragraph indentation will be preserved.
Note: By default, blank lines, spaces between words, and indentation are preserved in the output; successive input lines with different indentation are not joined; tabs are expanded on input and introduced on output.
Read : man fmt