интерфейс к системным справочным руководствам (an interface to the system reference manuals)
DEFAULTS
The order of sections to search may be overridden by the
environment variable $MANSECT or by the SECTION directive in
/usr/local/etc/man_db.conf. By default it is as follows:
1 n l 8 3 0 2 5 4 9 6 7
The formatted manual page is displayed using a pager. This can
be specified in a number of ways, or else will fall back to a
default (see option -P for details).
The filters are deciphered by a number of means. Firstly, the
command line option -p or the environment variable $MANROFFSEQ is
interrogated. If -p was not used and the environment variable
was not set, the initial line of the nroff file is parsed for a
preprocessor string. To contain a valid preprocessor string, the
first line must resemble
'\" <string>
where string can be any combination of letters described by
option -p below.
If none of the above methods provide any filter information, a
default set is used.
A formatting pipeline is formed from the filters and the primary
formatter (nroff or [tg]roff with -t) and executed.
Alternatively, if an executable program mandb_nfmt (or mandb_tfmt
with -t) exists in the man tree root, it is executed instead. It
gets passed the manual source file, the preprocessor string, and
optionally the device specified with -T or -E as arguments.
