path: root/manual/intro.me

.\" Copyright (C), 1995, Graeme W. Wilford. (Wilf.)
.\" Copyright (c) 2001, 2002, 2003, 2007 Colin Watson.
.\"
.\" You may distribute under the terms of the GNU General Public
.\" License as specified in the file COPYING that comes with the
.\" man-db distribution.
.\"
.\" Thu Sep 21 19:22:47 BST 1995  Wilf. (G.Wilford@ee.surrey.ac.uk) 
.\" 
.\" chap1.me
.BS 1 Introduction
.BS 2 "\*M"
.lp
\*M is a package that is designed to provide users with online information
in a fast and friendly manner while at the same time offering flexibility to
the system administrator.
.TS
tab(@);
l s s s
l lfB l.
It is made up of several user programs:
.sp 6p
.\" Leave the next line alone!
      @\(bu man@\- an interface to the on-line reference manuals
@\(bu whatis@\- search the manual page names
@\(bu apropos@\- search the manual page names and descriptions
@\(bu manpath@\- determine search path for manual pages
@\(bu lexgrog@\- directly read header information in manual pages
.T&
l s s s
l lfB l.
.sp 6p 
several maintenance programs:
.sp 6p
@\(bu mandb@\- create or update the manual page index caches
@\(bu catman@\- create or update the pre-formatted manual pages
.T&
l s s s
l lfB l.
.sp 6p
and a special pre-formatter that knows about compressed manual pages:
.sp 6p
@\(bu zsoelim@\- satisfy .so requests in roff input
.TE

In addition to these compiled programs, there are two shell scripts,
.b mkcatdirs
and
.b checkman
in the
.i tools
subdirectory.
These scripts aid the creation of cat directories and
check for duplicated manual pages, respectively.
.lp
The following manual pages are provided with this package to explain correct
format and usage.
.b man (1),
.b whatis (1),
.b apropos (1),
.b manpath (1),
.b lexgrog (1),
.b manpath (5),
.b mandb (8),
.b catman (8)
and
.b zsoelim (1).
.BS 3 "The concept"
.lp
\*M originally started out life as program suite man\-1.1B, written by John W.
Eaton <jwe@che.utexas.edu> and maintained by Rik Faith <faith@cs.unc.edu>
to which support proposed by the newly
formed FSSTND committee regarding cat directories was added.
.lp
Since then, \*M's most innovative feature: the database cache scheme\**
.(f
\** originally conceived after observing the actions of the Perl-based
manual pager suite, man-pl written by Tom Christiansen
<tchrist@convex.com>
.)f
has been significantly developed. The basic idea was to reduce manual page
search times to a minimum. The following piece of text is included from the
man-db-2.2 distribution:
.(q
The theory: If you go to a library to take a book out, what do you do?
.sp
a) Go and look where it might be on a micro-fiche/terminal, take a look
where it is supposed to be on the shelf, and then go look at the new
arrivals if it's not where it's supposed to be?
.sp
OR
.sp
b) Start at one end of the ground floor, look along every bookshelf
until you've completed that floor, then go up a level and start again
until you've found what you're looking for?
.)q
.lp
Since then the database
.b index
scheme has evolved greatly.
Every manual page and stray cat page on the system is registered in an
.b index
database cache which stores various details about the file including the
timestamp, the location and the whatis\**
.(f
\** one line description of the manual page
.)f
information.
This information is kept up to date by regular runs of
.b mandb .
In some configurations
.b man
also looks for filesystem changes each time it is invoked and helps to
keep the database cache current, but this imposes a penalty on manual page
search times.
.BS 2 "The manual page system"
.lp
The simplest manual page system will have a single manual page hierarchy.
This will typically be
.ip
.i /usr/share/man
.lp
beneath which will be several subdirectories of the form
.i man<sec>
where
.i <sec>
is
.b 1 ,
.b 2 ,
.b 3 ,
.b 4 ,
.b 5 ,
.b 6 ,
.b 7
or
.b 8 .
These are referred to as
.i sections
of the
manual.
Others may exist and they are not restricted to single
character names. eg.
.ip
.i /usr/share/man/manfoo
.lp
is a valid section subdirectory.
Other common sections include
.b 9 ,
.b n ,
.b l ,
.b p
and
.b o .
.lp
Within these section subdirectories reside the manual pages themselves. Their
filenames follow the pattern
.ip
.i /usr/share/man/man<sec>/<name>.<sec><ext>
.lp
where in most cases
.i <ext>
is an empty string.
An example is manual page
.b cp
.ip
.i /usr/share/man/man1/cp.1
.lp
which resides in
.i section
.b 1
and has no special
.i extension .
.lp
.BS 2 "Sections of the manual"
.lp
The manual is split up into sections to ease access and to cater for manual
pages that share the same name.
It is common for a program and function to share the same name.
.b kill
is a good example.
This is both a program which can be used to send a process a signal and
an operating system call with similar functionality.
Their manual pages are stored under sections
.b 1
and
.b 2
respectively.
Thus, sections are used to separate out the program manual pages from the
function manual pages and so on.
The table below shows the
.i section
numbers of the manual followed by the types of pages they contain.

.TS
center box tab (@);
c  | c
c  | l.
Section@Section contents
_
1@user executable programs or shell commands
2@system calls (functions provided by the kernel)
3@library calls (functions within system libraries)
4@special files (usually found in \fI/dev\fR)
5@file formats and conventions eg. \fI/etc/passwd\fR
6@games
7@macro packages and conventions eg. \fBman\fR(7), \fBgroff\fR(7).
8@system administration commands
9@kernel routines [\|Non-standard\|]
n@new [\|obsolete\|]
l@local [\|obsolete\|]
p@public [\|obsolete\|]
o@old [\|obsolete\|]
.TE

.BS 2 "The format of manual pages"
.lp
The format in which manual pages are stored is \*N/\*T or more generally \*R.
This is a typesetter style language\**
.(f
\** similar in some aspects to
.b TeX
.)f
which requires formatting before being viewed.
In fact some manual pages require pre-format processing to
correctly format tables or equations.
.lp
If the page is to be viewed on screen in a text environment, \*N is
used as the primary formatter. If the page is to be printed or displayed in a
graphical environment, \*T is used. Traditionally, \*T formatted files for a
.b C/A/T
(Computer aided Typesetter) which is now obsolete.

The \*(GN \*R (\*G\**)
.(f
\** Written by James Clark <jjc@jclark.com> and now maintained by
Ted Harding <ted.harding@nessie.mcc.ac.uk> and Werner Lemberg <wl@gnu.org>
.)f
suite of programs offer a choice of output types
including
.b X ,
.b dvi
and
.b postscript .
When configuring \*M, the preference is
to use \*G rather than \*T.
.BS 2 "Arguments to configure"
.lp
To allow the configuration program,
.b configure ,
to be non-interactive, it can be passed various options to alter the
default settings.
Generic
.b configure
options are discussed in
.i docs/INSTALL .
Options that are specific to the \*M package are described below.
.if r MAN-OPTIONS-ONLY \{
.lp
MAN\-OPTIONS\-BEGIN
\}
.lp
.ip \-\-enable\-cache\-owner[=ARG]
By default, system-wide cache files will be owned by user man.
Use this option with an argument to change the cache file owner.
.ip \-\-disable\-cache\-owner
Use this option to leave the ownership of system-wide cache files
unconstrained.
Users will be allowed to modify them.
.ip \-\-disable\-setuid
By default,
.b man
will be installed as a setuid program to the user that owns the
system-wide cache files.
Use this option to install
.b man
as a non-setuid program instead.
.ip \-\-enable\-mandirs=OS
By default, \*M supports manual page directories in any of several layouts
used by free and proprietary versions of \*U.
However, in certain cases, this can cause \*M to find the wrong page by
mistake, especially when the names of some manual pages on the system
contain periods.
Use this option with an argument of GNU, HPUX, IRIX, Solaris, or BSD
(or more than one of these, separated by commas) to support only the layouts
typically used on each of those systems.
Note that \*M is not currently capable of writing cat pages in the proper
BSD layout.
.ip \-\-with\-device=DEVICE
Use this flag to alter the default output device used by \*N. DEVICE is
passed to \*N with the \-T option.
.b configure
will test that \*N will run with the supplied device argument.
.ip \-\-with\-db=LIBRARY
configure will look for database interface libraries in the order gdbm,
Berkeley DB and finally ndbm and will #define appropriate variables relative
to the first one found.
To override the built-in order on platforms having a choice of interface
library, use this option to specify which library to use.
.ip \-\-enable\-automatic\-create
If this flag is used,
.b man
will automatically create index databases for users' private manual page
hierarchies.
.ip \-\-disable\-automatic\-update
Normally,
.b man
will update entries in index databases if it finds newly installed manual
pages (if the
.b \-\-update
flag is used) or delete entries if manual pages are removed.
This flag suppresses this behaviour.
.ip \-\-disable\-cats
Normally,
.b man
will automatically try to create cat files corresponding to manual files
when a manual page is read.
This flag suppresses this behaviour.
.if r MAN-OPTIONS-ONLY \{
.lp
MAN\-OPTIONS\-END
\}