2 Invoking groff

This chapter 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 them from their original counterparts provided by the host (see Environment). 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 incarnation of troff used. 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 almost all troff implementations⁴ (with more or less compatible changes). Similarly, we say ‘gpic’, ‘geqn’, and so on.