The groffer program supports many system variables, most of them
by courtesy of other programs. All environment variables of
groff(1) and GNU man(1) and some standard system variables are
honored.
Native groffer variables
GROFFER_OPT
Store options for a run of groffer. The options specified
in this variable are overridden by the options given on
the command line. The content of this variable is run
through the shell builtin 'eval', so arguments containing
whitespace or special shell characters should be quoted.
Do not forget to export this variable, otherwise it does
not exist during the run of groffer.
System variables
The following variables have a special meaning for groffer.
DISPLAY
If set, this variable indicates that the X Window System
is running. Testing this variable decides on whether
graphical or text output is generated. This variable
should not be changed by the user carelessly, but it can
be used to start the graphical groffer on a remote X
Window System terminal. For example, depending on your
system, groffer can be started on the second monitor by
the command
sh# DISPLAY=:0.1 groffer what.ever &
LC_ALL
LC_MESSAGES
LANG If one of these variables is set (in the above sequence),
its content is interpreted as the locale, the language to
be used, especially when retrieving man pages. A locale
name is typically of the form
language[_territory[.codeset[@modifier]]], where language
is an ISO 639 language code, territory is an ISO 3166
country code, and codeset is a character set or encoding
identifier like ISO-8859-1 or UTF-8; see setlocale(3).
The locale values C and POSIX stand for the default, i.e.
the man page directories without a language prefix. This
is the same behavior as when all 3 variables are unset.
PAGER This variable can be used to set the pager for the tty
output. For example, to disable the use of a pager
completely set this variable to the cat(1) program
sh# PAGER=cat groffer anything
PATH All programs within the groffer script are called without
a fixed path. Thus this environment variable determines
the set of programs used within the run of groffer.
groff variables
The groffer program internally calls groff, so all environment
variables documented in groff(1) are internally used within
groffer as well. The following variable has a direct meaning for
the groffer program.
GROFF_TMPDIR
If the value of this variable is an existing, writable
directory, groffer uses it for storing its temporary
files, just as groff does. See the groff(1) man page for
more details on the location of temporary files.
man variables
Parts of the functionality of the man program were implemented in
groffer; support for all environment variables documented in
man(1) was added to groffer, but the meaning was slightly
modified due to the different approach in groffer; but the user
interface is the same. The man environment variables can be
overwritten by options provided with MANOPT, which in turn is
overwritten by the command line.
EXTENSION
Restrict the search for man pages to files having this
extension. This is overridden by option --extension; see
there for details.
MANOPT This variable contains options as a preset for man(1). As
not all of these are relevant for groffer only the
essential parts of its value are extracted. The options
specified in this variable overwrite the values of the
other environment variables that are specific to man. All
options specified in this variable are overridden by the
options given on the command line.
MANPATH
If set, this variable contains the directories in which
the man page trees are stored. This is overridden by
option --manpath.
MANSECT
If this is a colon separated list of section names, the
search for man pages is restricted to those manual
sections in that order. This is overridden by option
--sections.
SYSTEM If this is set to a comma separated list of names these
are interpreted as man page trees for different operating
systems. This variable can be overwritten by option
--systems; see there for details.
The environment variable MANROFFSEQ is ignored by groffer because
the necessary preprocessors are determined automatically.
