Slackware Linux Essentials: Tutorial 02

Chapter 2 Help
Table of Contents
2.1 System Help
2.2 Online Help

Often there are times when you might need help with a specific command, setting up a program, or getting a piece of hardware to work. Maybe you simply want to understand a given command better, or see what other options are available to use with it. Luckily, there are a variety of ways that you can get the help you're looking for. When you install Slackware you have the option of installing packages from the “F” series which includes FAQs and HOWTOs. Programs also come with help about their options, configuration files, and usage.

2.1 System Help
2.1.1 man
The man command (short for “manual”) is the traditional form of online documentation in Unix and Linux operating systems. Comprised of specially formatted files, the “man pages”, are written for the vast majority of commands and are distributed with the software itself. Executing man somecommand will display the man page for (naturally) the command specified, in our example this would be the imaginary program somecommand.

As you might imagine, the amount of man pages can quickly add up, becoming overly confusing and seriously complicated, even for an advanced user. So, for this reason, man pages are grouped into enumerated sections. This system has been around for a very long time; enough so that you will often see commands, programs, and even programming library functions referred to with their man section number.

For example:

You might see a reference to man(1). The numbering tells you that “man” is documented in section 1 (user commands); you can specify that you want the section 1 man page for “man” with the command man 1 man. Specifying the section that man should look in is useful in the case of multiple items with the same name.

Table 2-1. Man Page Sections

Section Contents
Section 1 user commands (intro only)
Section 2 system calls
Section 3 C library calls
Section 4 devices (e.g., hd, sd)
Section 5 file formats and protocols (e.g., wtmp, /etc/passwd, nfs)
Section 6 games (intro only)
Section 7 conventions, macro packages, etc. (e.g., nroff, ascii)
Section 8 system administration (intro only)

In addition to man(1), there are the commands whatis(1) and apropos(1) available to you, whose shared purpose is to make it easier to find information in the man system.

The command whatis gives a very brief description of system commands, somewhat in the style of a pocket command reference.

Example:

% whatis whatis
whatis (1) - search the whatis database for complete words


The command apropos is used to search for a man page containing a given keyword.

Example:

% apropos wav
cdda2wav (1) - a sampling utility that dumps CD audio data into wav sound files
netwave_cs (4) - Xircom Creditcard Netwave device driver
oggdec (1) - simple decoder, Ogg Vorbis file to PCM audio file (WAV or RAW)
wavelan (4) - AT&T GIS WaveLAN ISA device driver
wavelan_cs (4) - AT&T GIS WaveLAN PCMCIA device driver
wvlan_cs (4) - Lucent WaveLAN/IEEE 802.11 device driver


If you'd like further information on any of these commands, read their man pages for the details. ;)

2.1.2 The /usr/doc Directory
The source for most packages that we build comes with some sort of documentation: README files, usage instructions, license files, etc. Any sort of documentation that comes with the source is included and installed on your system in the /usr/doc directory. Each program will (usually) install its own documentation in the order of:

/usr/doc/$program-$version

Where $program is the name of the program you are wanting to read about, and $version is (obviously) the appropriate version of software package installed on your system.

For example, to read the documentation for the command man(1) you would want to cd to:

% cd /usr/doc/man-$version


If reading the appropriate man page(s) doesn't provide you with enough information, or address what you're looking for in particular, the /usr/doc directory should be your next stop.

2.1.3 HOWTOs and mini-HOWTOs
It is in the truest spirit of the Open Source community that brings us to the HOWTO/mini-HOWTO collection. These files are exactly what they sound like - documents and guides describing how to do stuff. If you installed the HOWTO collection, the HOWTOs will be installed to /usr/doc/Linux-HOWTOs and the mini-HOWTOs to /usr/doc/Linux-mini-HOWTOs.

Also included in the same package series is a collection of FAQs, which is an acronym which stands for

Frequently
Asked
Questions

These documents are written in a “Question and answer” style for (surprise) Frequently Asked Questions. The FAQs can often be a very useful place to look if you're just looking for a “Quick Fix” to something. If you decide to install the FAQs during setup, you will find them installed to the /usr/doc/Linux-FAQs directory.

These files are well worth reading whenever you're not quite sure how to proceed with something. They cover an amazing range of topics, more often than not in a surprisingly detailed manner. Good stuff!

http://www.slackbook.org/html/help.html