2 Invoking groff

This section focuses on how to invoke the groff front end. This front end takes care of the details of constructing the pipeline among the preprocessors, gtroff and the postprocessor.

It has become a tradition that GNU programs get the prefix ‘g’ to distinguish it from its original counterparts provided by the host (see Environment, for more details). Thus, for example, geqn is GNU eqn. On operating systems like GNU/Linux or the Hurd, which don’t contain proprietary versions of troff, and on MS-DOS/MS-Windows, where troff and associated programs are not available at all, this prefix is omitted since GNU troff is the only used incarnation of troff. Exception: ‘groff’ is never replaced by ‘roff’.

In this document, we consequently say ‘gtroff’ when talking about the GNU troff program. All other implementations of troff are called AT&T troff, which is the common origin of all troff derivates (with more or less compatible changes). Similarly, we say ‘gpic’, ‘geqn’, etc.