roff

Roff is a family of text-formatting languages and processing systems used on Unix and Unix-like systems to format documents for printing or on-screen display. The name is traditionally traced to Runoff, one of the earliest programs for formatting text for line printers; roff was developed in the 1970s at Bell Labs and evolved into the troff/nroff/groff family. The core idea is that a plain text input contains formatting requests and macros, which are interpreted by a roff processor to produce paginated output.

In practice, roff consists of a pipeline: the input is processed by macro packages that provide higher-level formatting constructs, and then fed to a roff processor such as troff (for high-quality typeset output) or nroff (for terminal or simple device output). Troff and nroff are the main successors of the original roff, with troff typically producing PostScript or other printer formats, and nroff targeting terminal displays. These tools are foundational to many document workflows on Unix systems and are the historical basis for the later groff implementation.

A suite of preprocessors and macro packages extends roff’s capabilities, including eqn for mathematics, tbl for tables, and pic for diagrams. Groff, the GNU reimplementation, supports numerous macro packages (such as man, ms, and mm) and can emit a variety of output formats, including PostScript, PDF, and plain text. The roff family remains in use for formatting manuals, man pages, and older documentation, even as more modern tools have become prevalent in general publishing tasks.

Overall, roff represents a foundational, text-based approach to high-quality document formatting that persists primarily in Unix documentation and legacy systems.