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Two-Minute Drill
Here are some of the key points from the certification objectives in Chapter 1.
Basic Hardware Knowledge
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The Red Hat exams are given on computers built for an Intel-based 32-bit architecture.
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An Intel-architecture PC has three basic communications channels: IRQ ports, I/O addresses, and DMA channels.
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The latest version of Red Hat Enterprise Linux as certified should have at least 256MB of RAM.
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You can set up Linux on IDE, SCSI, USB, or IEEE 1394 hard drives. However, the BIOS of a PC can load Linux boot files only from the first two PATA, SATA, or SCSI
drives
.
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Basic Linux Knowledge
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Linux is managed through a series of text configuration files.
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Understanding text editors is a critical skill. If you ever have to recover your system with a rescue CD, you may not have access to the GUI and will need to know how to use a console-based text editor such as vi.
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Linux Filesystem Hierarchy and Structure
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Linux directories are organized to the Filesystem Hierarchy Standard (FHS).
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In the FHS, devices such as mice and hard drives are grouped in the /dev directory. Some /dev files have logical
names
such as dvdwriter and are linked to the actual device files.
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FHS partitions can be managed and formatted with the
fdisk
,
fsck
, and
mkfs
commands.
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The Logical Volume Manager allows you to consolidate multiple partitions in one filesystem, on one directory.
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Once configured, Linux directories can be mounted on a partition through /etc/fstab or directly with the
mount
command.
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Basic File Operations and Manipulation
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Linux administrators need to know how to use the command line interface.
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Basic commands allow you to navigate, find the files that you need, read file contents, create new files, and more.
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File filters allow you to search through the files
themselves
for specific citations or other file characteristics.
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Administrative commands allow you to manage Linux in a number of ways, including running processes and managing logged-in users.
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Printing
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The default Red Hat Enterprise Linux print system is CUPS.
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You can configure printers by directly editing the files in the /etc/cups directory or by opening the Red Hat Printer Configuration tool with the
system-config-printer
command.
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Shells
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Command lines are based on a shell.
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With the right permissions, you can set up shell programs in executable scripts.
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The way a shell works depends on the settings in its variables and parameters. Some
variables
and parameters are grouped in the inherited environment, which maintains settings from shell to shell.
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With stdin,
stdout
, and stderr, you can manage different data streams.
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Basic Security
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Basic security within Linux is based on file permissions, users, groups, and
umask
.
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The SUID and SGID bits allow you to share owner-level permissions with different users and groups.
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Shadow passwords hide user authentication data. The Shadow Password Suite protects user and
group
passwords in files that should be accessible only to the root
user
.
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System Administration
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While it's normally best to log in as a regular user, it's faster to log in as the root user for the RHCE and RHCT exams.
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Standard files for new users are kept in /etc/skel.
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Daemons are processes that run in the background.
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Network service can be controlled through scripts in the /etc/init.d and /etc/ xinetd.d directories.
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The
cron
daemon helps you schedule different jobs, including backup and restore jobs, which should be done when network use is at a minimum.
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When you have problems, system log files, as organized by /etc/syslog.conf, provide important clues to the causes.
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Basic TCP/IP Networking
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Most of the work in TCP/IP networking is in configuring IP addresses.
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There are three different sets of private IPv4 addresses suitable for setting up TCP/IP on a LAN.
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IPv6 addresses include all available IPv4 addresses. If the first three bits of an IPv6 address are 001, that is a unicast address-in other words, one that is associated with a specific computer or other device.
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The first 48 bits of an IPv6 address are typically associated with a specific network.
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Tools such as
ping
,
ping6
,
ifconfig
, and
netstat
can help you diagnose problems on that LAN.
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Name
resolution configuration files determine how your computer finds the right IP address.
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Familiarity with Standard Network Services
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There are a number of standard network services, including NFS, sendmail, POP, IMAP, FTP, DNS, DHCP, Samba, Apache, and NIS.
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Each of these services, when installed, can be configured to start and stop through the scripts located in the /etc/rc.d/init.d or /etc/xinetd.d directories.
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Basic Network Security
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Basic network security settings can depend on allowing or
denying
access to different computers by their IP addresses or by the desired TCP/IP port.
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Computers behind a firewall can be protected through Network Address Translation or various
iptables
commands.
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Other Basic Prerequisite Skills per the Red Hat Exam Prep Guide
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While GUI e-mail
clients
should be trivial, it's important to know how to configure a command line e-mail client.
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While GUI Web browsers should be trivial for serious Red Hat exam candidates, it can help to know a text-based browser such as
elinks
.
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While GUI FTP clients should be trivial for serious Red Hat exam candidates, it can help to understand a text-based FTP client such as
lftp
.
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Downloading the Red Hat Enterprise Linux Installation CDs
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There is no evidence that you need to know how to download the Red Hat installation CDs for the Red Hat exams.
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While the best option is to download the RHEL 5 CDs from the Red Hat Network,
excellent
options are available.
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You can use the rebuild distributions to prepare for the Red Hat exams. Their distributions are built on the same source code used by Red Hat for RHEL 5.
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