groff: Macro Directories
2.3 Macro Directories
=====================
All macro file names must be named 'NAME.tmac' or 'tmac.NAME' to make
the '-mNAME' command-line option work. The 'mso' request doesn't have
this restriction; any file name can be used, and 'gtroff' won't try to
append or prepend the 'tmac' string.
Macro files are kept in the "tmac directories", all of which
constitute the "tmac path". The elements of the search path for macro
files are (in that order):
* The directories specified with 'gtroff''s or 'groff''s '-M'
command-line option.
* The directories given in the 'GROFF_TMAC_PATH' environment
variable.
* The current directory (only if in unsafe mode using the '-U'
command-line switch).
* The home directory.
* A platform-dependent directory, a site-specific
(platform-independent) directory, and the main tmac directory; the
default locations are
/usr/local/lib/groff/site-tmac
/usr/local/share/groff/site-tmac
/usr/local/share/groff/1.22.3/tmac
assuming that the version of 'groff' is 1.22.3, and the
installation prefix was '/usr/local'. It is possible to fine-tune
those directories during the installation process.