Most of the documentation is targeted at the user of a specific program, command, or library function, but there are also some more general tutorials. The documents come as manual pages, Info files, plain text files, HTML files, and in various other formats. The Debian on-line documentation system gives access to all of them via a WWW browser by converting the documents to HTML, if possible.
Manual pages make it possible to find information quickly. The manual pages form the UNIX reference manual, but they are not very useful if you haven't used a UNIX system before. Most manual pages assume that you understand the common concepts of using UNIX. You should start by reading a tutorial (see below). Then, when you need to learn a new command, you can read its manual page.
Manual pages are read with the man
command. You give the
name of the manual page (usually the same as the command) as the
argument. For example, to read the manual page for the ls
command, you'd give the following command:
man ls
You can also read manual pages using your WWW browser
through the Debian on-line documentation system.
Few people outside the GNU Project use Texinfo, but since GNU has produced so much software, there are many Info files. Since a manual page should be short, and an Info file need not be, the Info files are sometimes easier to read.
Info files can be read directly using the GNU Emacs help system
(started with C-h i
from within Emacs), or the standalone
Info browser (started with info
from the shell).
You can also read manual pages using your WWW browser
through the info2www interface that comes with the
Debian on-line documentation system.
/usr/doc
(see below).It is becoming more common for complicated programs to include documentation in HTML or Postscript format, in addition to (sometimes incomplete) manual pages. HTML is the markup language that WWW uses, and all such documents are easily accessible via the Debian on-line documentation system. Postscript, however, is a complicated typesetting language, and it cannot easily be converted to other formats. There is no easy way to read the Postscript manuals via the Debian on-line documentation system.
/usr/man
,
/usr/X11R6/man
, and /usr/local/man
. Each
manual page is in its own file. They are written using an old
markup language (see documentation for groff
and the
mandoc
macros), and are formatted into a more readable
format using nroff
. Since the formatting can be slow, the
formatted page is stored into /var/catman
; that directory
is automatically cleaned from old formatted versions.
Info documents are stored in /usr/info
. Info files are
not quite plain text, so they also need to be formatted for easier reading.
However, this formatting is fast enough that the formatted version is
not saved.
Each installed Debian package creates its own documentation directory
below /usr/doc
. For example, documentation for Debian
itself is in /usr/doc/debian
. All documentation that is
not manual pages of Info files is stored in the package's documentation
directory.
All packages share a couple directories below /usr/doc
.
The /usr/doc/copyright
directory contains the copyright
statements for all packages, and /usr/doc/examples
contains
example configurations and programs.
At some point, you should read the manual pages for your shell (bash), and some of the essential file handling commands (ls, less, cd, mkdir, rmdir, cp, mv, rm). You might also want to check out Midnight Commander and GNU Interactive Tools, which can be nicer to use than the traditional commands. Also read the manual for your editor (for example, Pico, ae, Emacs, Jed, vim, nvi, or elvis, depending on taste and on what is installed). After that, browse the Debian on-line documentation system and read about whatever happens to interest you.