groff

Groff is a document formatting system. Groff takes standard text and
formatting commands as input and produces formatted output. The
created documents can be shown on a display or printed on a printer.
Groff's formatting commands allow you to specify font type and size,
bold type, italic type, the number and size of columns on a page, and
more.

Groff can also be used to format man pages. If you are going to use
groff with the X Window System, you will also need to install the
groff-gxditview package.