You should familiarize yourself with an important source of information in Red Hat Linux. Every so often, you see instructions that ask you to enter a Linux command. After a while, you are bound to get to the point at which you vaguely recall a command's name, but you cannot remember the exact syntax of what you are supposed to type. This is a situation in which the Linux online manual pages can come to your rescue.
Insider Insight
To try out the commands described in this section, you have to open a terminal window in GNOME. Select Main Menu>System Tools>Terminal (refer to Figure 7-2). This opens a terminal window in which you can type Linux commands.
You can view the manual page-commonly referred to as the man page-for a command by using the man command. (You do have to remember that command to access online help.) For example, to view the man page for the modprobe command, type the following command in a terminal window:
man modprobe
The man command then displays the help information page by page. Press the Spacebar to move to the next page. Press b to move backward by a page. To look for a specific word in the man page, press the forward slash, type the word, and press Enter. For example, to search for the word 'debug,' type /debug, and press Enter. When you finish reading the man page, press q to return to the Linux command prompt.
Having touted the usefulness of the online help pages, I must point out that the term Linux command refers to any executable file, ranging from a script file that contains other Linux commands to standard Linux executable programs. Although man pages exist for most standard programs, many programs do not have any online help. Nevertheless, whenever you are having difficulty recalling some command, it is worthwhile to use the man command to see whether any online help for that command exists.
If you do not want to read the full man page, you can use whatis to read a one-line summary of a command. For example, here's how you use whatis to see a brief description of the modprobe command:
whatis modprobe
modprobe (8) - high level handling of loadable module
The number (8) indicates the man page section where the modprobe command is listed. You should try the whatis command to view one-line descriptions of a few other commands.
You can use the shell's wildcard feature and the whatis command to explore the files in various system directories such as /bin, /sbin, /usr/sbin, /usr/bin, and so on. Simply change the directory to one of interest and type whatis * to view one-line descriptions of the programs in that directory. (whatis displays information for those programs for which such information is available.) For example, here is how you can explore the /sbin directory:
cd /sbin; whatis * | more
addpart: nothing appropriate
adsl-connect (8) - Shell script to manage a PPPoE link
adsl-setup (8) - Shell script to configure Roaring Penguin PPPoE clie
nt
adsl-start (8) - Shell script to bring up a PPPoE link
adsl-status (8) - Shell script to report on status of PPPoE link
adsl-stop (8) - Shell script to shut down a PPPoE link
agetty (8) - alternative Linux getty
arp (7) - Linux ARP kernel module
arp (8) - manipulate the system ARP cache
arping (8) - send ARP REQUEST to a neighbour host
arytst: nothing appropriate
avmcapictrl (8) - Add, reset or remove active AVM cards and load firmw
are
badblocks (8) - search a device for bad blocks
blockdev (8) - call block device ioctls from the command line
capiinit: nothing appropriate
cardctl (8) - PCMCIA card control utility
cardmgr (8) - PCMCIA device manager
chkconfig (8) - updates and queries runlevel information for system
services
clock (3) - Determine processor time
... rest of the output not shown ...
As you can see, the output is an alphabetic list of all programs in the current directory, along with the one-line descriptions where available. The whatis command displays a message saying nothing appropriate if there is no information available for a program.
The man and whatis commands are useful when you know the name of a command. If you do not know the exact name of a command, you can use the apropos command to search for a command by a keyword (or even a part of a word). For example, if you remember that the command contains the word probe, type the following apropos command to search:
apropos probe
modprobe (8) - high level handling of loadable modules
partprobe (8) - inform the OS of partition table changes
scanpci (1x) - scan/probe PCI buses
In this case, the search result shows three candidate commands, each with a brief description. You can then select the command that does what you want to do.
Insider Insight
If apropos displays a long list of commands that scroll by too fast for you to read, you can type apropos keyword | more to view the output one screen at a time.
Another form of online documentation you can refer to are the HOWTO files, which you can access by visiting the Linux Documentation Project (LDP) website http://www.redhat.com/mirrors/LDP/. (Click the earth icon on the GNOME Panel to launch the Mozilla Web browser.) On that Web page, you find (among other things) links to Frequently Asked Questions (FAQs) and HOWTOs. You can click the HOWTOs link and download (or read) HOWTO documents in several formats, including text and HTML. For example, if you click to view plain-text HOWTOs, the Web browser shows a list of HOWTO files.
Each HOWTO file contains information about some area of Linux, such as the hardware it supports or how to create a boot disk. As you scroll through the list, you find over 230 HOWTO files. Table 7-1 lists and briefly describes some of these HOWTO files. To view any of these files, click the name; the Web browser should display the full text file.
Insider Insight
Near the beginning of the list of HOWTO files, you find a folder named mini. Click that link to view a list of mini-HOWTOs, which cover many more narrowly focused topics.
Table 7-1: Some Linux HOWTO Files
HOWTO Filename
Contents
ADSL-Bandwidth-Management-HOWTO
How to configure a Linux router to more effectively manage outbound traffic on an ADSL modem or cable modem
ATA-RAID-HOWTO
How to install Linux on an Intel Pentium- compatible PC with an ATA RAID Controller and at least two hard disks
AX25-HOWTO
How to install and configure Linux to support the AX.25 packet radio protocol used by Amateur Radio Operators worldwide
Accessibility-HOWTO
How to make Linux accessible to persons with disabilities
Adv-Routing-HOWTO
How to do perform advanced routing with the IP routing capabilities built into Linux 2.2 and 2.4 kernels
Apache-Compile-HOWTO
How to compile the Apache Web server with the modules such as mod_perl, mod_jserv, and mod_php
Apache-Overview-HOWTO
An overview of the Apache Web server and other associated commercial and open source software
Apache-WebDAV-LDAP-HOWTO
How to set up an Apache-based WebDAV (Web enabled Distributed Authoring and Versioning) server that can authenticate against a LDAP server
Assembly-HOWTO
How to program in assembly language in Linux
Authentication-Gateway-HOWTO
How to set up an authentication gateway for wireless networks in Linux
Bash-Prompt-HOWTO
How to use the Bash shell (command processor)
Belgian-HOWTO
How to configure Linux for Belgian users
BootPrompt-HOWTO
A list of arguments that can be passed to Linux at boot time (at the LILO boot: prompt)
Bootdisk-HOWTO
How to create boot, root, and other utility disks for Linux
C-C++Beautifier-HOWTO
How to beautifully format C and C++ programs so that they are more readable
Cable-Modem-HOWTO
How to connect a Linux system to a cable modem or cable Internet service provider
CD-Distributions-EN-HOWTO
A list of English-language Linux distributions, with particular focus on commercial CD-ROM distributions
CD-Writing-HOWTO
How to record a CD-ROM using a CD Recorder installed in a Linux system
CDROM-HOWTO
How to install, configure, and use CD-ROM drives with Linux
CVS-RCS-HOWTO
How to set up CVS and RCS source code control systems
Cable-Modem-Providers-HOWTO
How to connect a Linux system with various cable modem-based Internet service providers
Chroot-BIND HOWTO
How to install and configure a BIND 8 name server in a secure manner
Clone-HOWTO
How to boot Linux using GRUB and save partition images to and restore from a TFTP server
Cluster-HOWTO
How to build and configure high-performance Linux computing clusters
Config-HOWTO
How to configure the most common applications in Linux
DB2-HOWTO
How to install DB2 Universal Database Version 7.1 for Linux
DNS-HOWTO
How to set up Domain Name Service (DNS) on a Linux system
DOS-Win-to-Linux-HOWTO
How to apply your DOS and Windows knowledge to the Linux environment
DOS-to-Linux-HOWTO
How to apply your knowledge of MS-DOS in Linux
DSL-HOWTO
How to set up and use high-speed DSL (Digital Subscriber Line) connections to the Internet
DVD-HOWTO
How to play DVD movies in Linux
Diskless-HOWTO
How to set up a diskless Linux system
DocBook-Demystification-HOWTO
Explanation of the DocBook markup system, used to write technical documentation for open-source projects hosted on Linux
DocBook-OpenJade-SGML-XML-HOWTO
How to set up OpenJade to process SGML/XML DocBook documents
Emacs-Beginner-HOWTO
How to use the Emacs editor in Linux
Enterprise-Java-for-Linux-HOWTO
How to set up an Enterprise Java environment on Linux
Ethernet-HOWTO
How to configure and use Ethernet network adapters with Linux
Filesystems-HOWTO
How to access various file systems
Finnish-HOWTO
How to set up Linux for the Finnish language. (Except for the initial paragraph, the HOWTO itself is in Finnish.)
Firewall-HOWTO
How to set up an Internet firewall on a Linux system
Font-HOWTO
A comprehensive source of information about using different types of fonts in Linux
Framebuffer-HOWTO
How to use framebuffer devices (an abstraction of graphics hardware) in Linux
Francophones-HOWTO
How to set up Linux for the French language. (This HOWTO is in French.)
From-PowerUp-To-Bash-Prompt-HOWTO
How Linux boots itself
Ftape-HOWTO
How to set up and use floppy tape drives (QIC-40, QIC-80, QIC-3010, and QIC-3020- compatible tape drives that connect to your PC through the floppy disk controller) in Linux
Game-Server-HOWTO
How to install, configure, and maintain servers for some popular multiplayer games such as Quake II and Quake III Arena
GCC-HOWTO
How to set up and use the GNU C compiler and development libraries in Linux
German-HOWTO
How to use Linux with the German character set. (This HOWTO is in German.)
Glibc2-HOWTO
How to install and use the GNU C Library version 2 (libc 6) on Linux systems
Hardware-HOWTO
A list of hardware known to work with Linux; and how to locate any necessary drivers
Hebrew-HOWTO
How to support the Hebrew character set in X Window System and text-mode screens
Hellenic-HOWTO
How to use Linux with the Greek character set. (This HOWTO is in Greek.)
HighQuality-Apps-HOWTO
How to create Linux applications that are highly integrated with the operating system and provides security and ease of use
HOWTO-HOWTO
How to write a HOWTO document
HOWTO-INDEX
Index of all HOWTOs
Infrared-HOWTO
How to use IrDA-compliant infrared devices in Linux (IrDA is a standard for infrared wireless communication at speeds ranging from 2400bps to 4Mbps)
IngresII-HOWTO
How to install the Ingres II Relational Database Management System on Linux
Installation-HOWTO
How to obtain and install Linux
Intranet-Server-HOWTO
How to use a Linux system in an Intranet that ties together Unix, Novell Netware, Windows NT, and Windows 95 systems
IP-Masquerade-HOWTO
How to enable the IP Masquerading feature on a Linux system
IPCHAINS-HOWTO
How to obtain, install, and configure the enhanced IP firewall chains software for Linux, including some ideas about how you might use the ipchains tool (ipchains replaces the older ipfwadm tool)
IPX-HOWTO
How to obtain, install, and configure various software that use the Linux support for IPX protocol (IPX is used by Novell NetWare)
ISP-Hookup-HOWTO
How to connect a Linux system to an Internet service provider (ISP) via a dial-up modem connection
ISP-Setup-RedHat-HOWTO
How to set up a Red Hat Linux system for dial-in, virtual Web hosting, email, POP3, and FTP
Italian-HOWTO
How to set up Linux for the Italian language. (This HOWTO is in Italian.)
Java-CGI-HOWTO
How to develop and use Java programs in Linux
Java-Decompiler-HOWTO
How to decompile the Java class files
Jaz-Drive-HOWTO
How to use 1GB and 2GB Iomega Jaz drives in Linux
KDE-GUI-Login-Configuration-HOWTO
How to customize the KDE GUI login screen
Kernel-HOWTO
How to upgrade and rebuild the Linux kernel
KernelAnalysis-HOWTO
Description of the Linux kernel and how it works
Keyboard-and-Console-HOWTO
How to use various Linux utilities to configure the keyboard and the console (the text-mode screen)
Kickstart-HOWTO
How to use the Red Hat Linux Kickstart system to install an identical version of Linux on a large number of systems
Kiosk-HOWTO
How to set up a Web-based kiosk using Linux, X, Netscape Navigator, and a trackball
Kodak-Digitalcam-HOWTO
How to get a Kodak digital camera to work in Linux
Laptop-HOWTO
How to install and use Linux on laptop computers
LDAP-HOWTO
How to install, configure, run, and maintain a Lightweight Directory Access Protocol (LDAP) server on a Linux system
LDP-Reviewer-HOWTO
How to review Linux Documentation Project (LDP) documentation
LILO-crash-rescue-HOWTO
How to recover from Linux system failures when you use the LILO boot loader
Linmodem-HOWTO
How to use Winmodems in Linux
Linux+IPv6-HOWTO
How to install, configure, and use IPv6 applications in Linux
Linux+Win9x+Grub-HOWTO
How to use the GRUB boot loader to support dual-booting of Windows and Linux
Linux+XFS-HOWTO
How to build a Linux system that uses the SGI XFS journaling file system
Linux-Complete-Backup-and- Recovery-HOWTO
How to back up a Linux system so as to be able to recover from a complete disk crash and how to make that recovery
LinuxDoc+Emacs+Ispell-HOWTO
How to use Emacs and ispell to write documents such as HOWTOs for the Linux Documentation Project
Linux-Init-HOWTO
Description of the Linux 2.4 kernel initialization sequence on IA-32 processors
LVM-HOWTO
How to build, install, and configure Logical Volume Manager (LVM) for Linux
MIDI-HOWTO
Description of hardware, software, and procedures needed to play and sequence using MIDI devices in Linux
MILO-HOWTO
How to set up and use the Miniloader (MILO) for Linux on Alpha AXP-based systems. (Just as LILO loads and starts Linux on Intel-based PCs, MILO loads Linux on Alpha systems.)
Mail-Administrator-HOWTO
How to perform system-administration tasks related to electronic mail (email) systems in Linux
Mail-User-HOWTO
Information for users of the email system
Majordomo-MajorCool-HOWTO
How to install Majordomo Mailing List Software and the MajorCool utility to manage Majordomo lists on Linux
Masquerading-Simple-HOWTO
How to set up IP masquerading using iptables
Medicine-HOWTO
Description of Linux software for medical sciences
MIPS-HOWTO
How to obtain and use the version of Linux for the MIPS processors from Silicon Graphics. (The MIPS processors are used in many systems, ranging from Silicon Graphics workstations to Nintendo 64 game consoles.)
Modem-HOWTO
How to select, connect, configure, and use modems in Linux
Modem-Dialup-NT-HOWTO
How to set up the modem to support dial-up networking with a remote server such as Windows NT Remote Access Server (RAS) or Linux
Module-HOWTO
How to create and use loadable kernel modules (LKMs) in Linux
Mosix-HOWTO
How to use openMosix, a software package that turns a network of Linux systems into a computer cluster
MP3-HOWTO
How to encode and play MP3 sound files in Linux
Multi-Disk-HOWTO
How to best use multiple disks and partitions in Linux
Multicast-HOWTO
Information about multicasting over TCP/IP networking
Mutt-GnuPG-PGP-HOWTO
How to configure Mutt-i, PGP, and various versions of GnuPG in order to set up a mail reader with encryption and digital-signing capabilities
Net-HOWTO
Description of all Linux Networking implementations
NetMeeting-HOWTO
How to configure Linux for interoperability with Microsoft NetMeeting
Network-boot-HOWTO
How to set up a Linux server to support booting diskless Linux clients using an IP network
Network-Install-HOWTO
How to install Linux over a local area network (LAN)
Networking-Overview-HOWTO
An overview of networking capabilities of Linux
NFS-HOWTO
How to set up an NFS (Network File System) server and client in Linux
NIS-HOWTO
How to configure NIS (Network Information Service) in Linux
Online-Troubleshooting-HOWTO
How to use resources available on the Internet to troubleshoot Linux-related problems
Optical-Disk-HOWTO
How to install and configure optical disk drives in Linux (includes detailed coverage of the Panasonic LF1000 PD Phase change optical drive with the SCSI-II interface)
Oracle-7-HOWTO
How to install and configure the Oracle Database Server on a Linux system
Oracle-8-HOWTO
How to install and get started with Oracle 8i Enterprise Edition for Linux
Oracle8-on-RH7X-HOWTO
How to install Oracle 8i, version 8.1.7 Enterprise Edition for Linux on a Red Hat 7.x system
PalmOS-HOWTO
How to use a PalmOS device (such as Palm III) with Linux
Parallel-Processing-HOWTO
How to use parallel processing approaches such as SMP (Symmetric Multiprocessing) Linux systems, clusters of networked Linux systems, and parallel execution using multimedia instructions (e.g., MMX), and attached (parallel) processors hosted by a Linux system
PCI-HOWTO
Information on Linux's support for the PCI (Peripheral Component Interconnect) bus architecture
PCMCIA-HOWTO
How to install and use PCMCIA (Personal Computer Memory Card International Association) Card Services in Linux
PHP-HOWTO
How to develop Web applications using PHP, a server-side HTML scripting language
Plug-and-Play-HOWTO
How to support Plug-and-Play (PnP) devices in Linux
Polish-HOWTO
How to set up Linux for the Polish language. (This HOWTO is in Polish.)
Portuguese-HOWTO
How to set up Linux for the Portuguese language. (This HOWTO is in Portuguese.)
PostgreSQL-HOWTO
How to set up and use the PostgreSQL database engine in Linux
PPP-HOWTO
How to set up and use Point-to-Point Protocol (PPP) networking in Linux
Printing-HOWTO
How to set up printing in Linux
Printing-Usage-HOWTO
How to use the print spooling system in Linux
Program-Library-HOWTO
How to create and use program libraries in Linux (aimed at programmers)
Quake-HOWTO
How to install, run, and troubleshoot Quake, QuakeWorld and Quake II in Linux (these are 3D action games developed by id Software)
Querying-libiptc-HOWTO
How to use the libiptc library included in the iptables package
RedHat-CD-HOWTO
How to make your own CDs from the Red Hat Linux distribution that are equivalent to the ones commercially available from Red Hat
Remote-Serial-Console-HOWTO
How to set up Linux to support a terminal or modem attached to the serial port
Root-RAID-HOWTO
How to create a root-mounted RAID (Redundant Array of Inexpensive Disks) file system in Linux
RPM-HOWTO
How to use the Red Hat Package Manager (RPM) in Linux
RTLinux-HOWTO
How to set up and run RTLinux (real-time Linux)
SCSI-2.4-HOWTO
Description of the SCSI subsystem in the Linux 2.4 kernel
SCSI-Generic-HOWTO
Description of the SCSI Generic driver (sg) found in the Linux 2.4 kernel
SCSI-Programming-HOWTO
Information on programming the SCSI device driver in Linux (useful for programmers who want to add support for a new SCSI device in Linux)
Secure-Programs-HOWTO
How to write secure programs for Linux and UNIX systems
Security-HOWTO
An overview of security issues in a Linux system
Security-Quickstart-HOWTO
An overview of the basic steps required to secure a Linux system from intrusion
Security-Quickstart-Redhat-HOWTO
An overview of the basic steps required to secure a Red Hat Linux system from intrusion
Sentry-Firewall-CD-HOWTO
How to set up a firewall using the Sentry Firewall CD (http://www.SentryFirewall.com/)
Serbian-HOWTO
How to configure Linux for Serbian users. (This HOWTO is in Serbian.)
Serial-HOWTO
How to set up serial communication devices in Linux
Serial-Programming-HOWTO
How to program the serial port in Linux
Shadow-Password-HOWTO
How to obtain, install, and configure the password Shadow Suite in Linux (password shadowing provides for more secure passwords than the ones stored in the /etc/passwd file)
Slovenian-HOWTO
How to configure Linux for Slovenian users. (This HOWTO is in Slovenian.)
SMB-HOWTO
How to use the Server Message Block (SMB) protocol, also called the NetBIOS or LAN Manager protocol, with Linux
SMP-HOWTO
Information on configuring Symmetric Multiprocessing (SMP) on Linux systems with multiple processors
Snort-Statistics-HOWTO
How to configure Snort version 1.8.3, a Network Intrusion Detection System (NIDS), to gather statistics about network packets
Software-Building-HOWTO
How to build and install UNIX software distributions in Linux
Software-RAID-HOWTO
How to use Software RAID (software-supported virtual redundant disks) in Linux
Software-Release-Practice-HOWTO
Describes the good software release practices of Linux Open Source projects
Sound-HOWTO
How to enable support for sound hardware in Linux
Sound-Playing-HOWTO
Lists many sound file formats and the applications that can be used to play sound in Linux
Spanish-HOWTO
How to configure Linux for Spanish-speaking users. (This HOWTO is in Spanish.)
Speech-Recognition-HOWTO
Description and use of automatic speech recognition software in Linux
SRM-HOWTO
How to boot an Alpha-based Linux system using the SRM (System Reference Manual) firmware, which is the firmware normally used to boot DEC Unix on Alpha
SSL-Certificates-HOWTO
How to manage a certificate authority (CA) and issue or sign certificates to be used for secure Web or secure email using Secure Sockets Layer (SSL)
SSL-RedHat-HOWTO
How to build a secure Apache Web server in Red Hat Linux
TclTk-HOWTO
How to install, configure, and use the Tcl/Tk programming environment in Linux
TeTeX-HOWTO
How to install and use the teTeX TeX (pronounced tech as in technology) and LaTeX document formatting software in Linux
Text-Terminal-HOWTO
How to install and use text terminals (typically connected to multiport serial cards or a terminal server) with a Linux host
Thai-HOWTO
How to set up Linux for the Thai language
TimePrecision-HOWTO
How to maintain accurate date and time in Linux
Tips-HOWTO
Hints and tips to make Linux more useful and fun
UMSDOS-HOWTO
How to install and use the UMSDOS file system that lets you install Linux in an MS-DOS directory
Unicode-HOWTO
How to set up a Linux system so that it uses UTF-8 as text encoding
Unix-Internet-Fundamentals-HOWTO
Nontechnical description of how PCs, UNIX-like operating systems, and the Internet work
UPS-HOWTO
How to use an uninterruptible power supply (UPS) with Linux
USB-Digital-Camera-HOWTO
How to use in Linux a digital camera with Universal Serial Bus (USB) mass storage capabilities
Usenet-News-HOWTO
How to set up and access Usenet news in Linux
User-Authentication-HOWTO
How to secure user authentication in Linux
User-Group-HOWTO
How to establish and run a Linux User Group
UUCP-HOWTO
How to set up and use the Unix-to-Unix Copy (UUCP) software in Linux
VAR-HOWTO
Lists Linux Value Added Resellers (VARs)
Vim-HOWTO
How to set up and use the vim (Vi Improved) editor with color highlighting
Virtual-Services-HOWTO
How to support virtual services on a Linux system so that a single machine can recognize multiple IP addresses without multiple network cards
VME-HOWTO
How to run Linux on VMEbus systems
VMS-to-Linux-HOWTO
How to transition from VMS to Linux. (VMS is an operating system that runs on VAX systems from Digital Equipment Corporation.)
VoIP-HOWTO
Description of voice over IP (VoIP) system and software
VPN-HOWTO
How to configure a Linux system to support a virtual private network (VPN)
VPN-Masquerade-HOWTO
How to configure a Linux firewall to masquerade IPsec and Point-to-Point Tunneling Protocol (PPTP) traffic to support
