by Trent A. Fisher and Werner Lemberg - The GNU Operating System

Chapter 2: Invoking groff 13
GROFF_TMPDIR
The directory in which groff creates temporary files. If this is
not set and TMPDIR is set, temporary files are created in that
directory. Otherwise temporary files are created in a systemdependent
default directory (on Unix and GNU/Linux systems,
this is usually ‘/tmp’). grops, grefer, pre-grohtml, and postgrohtml
can create temporary files in this directory.
GROFF_TYPESETTER
The default output device.
Note that MS-DOS and MS-Windows ports of groff use semi-colons,
rather than colons, to separate the directories in the lists described above.
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/1.21/tmac
assuming that the version of groff is 1.21, and the installation prefix
was ‘/usr/local’. It is possible to fine-tune those directories during
the installation process.
2.4 Font Directories
Basically, there is no restriction how font files for groff are named and how
long font names are; however, to make the font family mechanism work (see
Section 5.17.2 [Font Families], page 109), fonts within a family should start
with the family name, followed by the shape. For example, the Times family
uses ‘T’ for the family name and ‘R’, ‘B’, ‘I’, and ‘BI’ to indicate the shapes