Nroff

nroff (short for "new roff") is a text-formattingprogram on Unix and Unix-likeoperating systems. It produces output suitable for simple fixed-width printers and terminal windows. It is an integral part of the Unix help system, being used to format man pages for display.

nroff and the related troff were both developed from the original roff. While nroff was intended to produce output on terminals and line printers, troff was intended to produce output on typesetting systems. Both used the same underlying markup and a single source file could normally be used by nroff or troff without change.