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Basic Commands

Command's Purpose

MS-DOS

Linux

Basic Linux Example

Copies files

copy

cp

cp thisfile.txt /home/thisdirectory

Moves files

move

mv

mv thisfile.txt /home/thisdirectory

Lists files

dir

ls

ls

Clears screen

cls

clear

clear

Closes prompt window

exit

exit

exit

Displays or sets date

date

date

date

Deletes files

del

rm

rm thisfile.txt

"Echoes" output on the screen

echo

echo

echo this message

Edits files with simple text editor

edit

pico[a]

pico thisfile.txt

Compares the contents of files

fc

diff

diff file1 file2

Finds a string of text in a file

find

grep

grep this word or phrase thisfile.txt

Formats a diskette

format a: (if diskette is in A:)

mke2fs (or mformat[b])

/sbin/mke2fs /dev/fd0 (/dev/fd0 is the Linux equivalent of A:)

Displays command help

command /?

man[c]

man command

Creates a directory

mkdir

mkdir

mkdir directory

View a file

more

less[d]

less thisfile.txt

Renames a file

ren

mv

mv thisfile.txt thatfile.txt[e]

Displays your location in the file system

chdir

pwd

pwd

Changes directories with a specified path (absolute path)

cd pathname

cd pathname

cd /directory/directory

Changes directories with a relative path

cd ..

cd ..

cd ..

Displays the time

time

date

date

RAM and use

mem

free

free

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Booting Process

1. Power on : Power on the machine.

2. BIOS (Basic input/Output System) initialization.

3. POST (Power On Self Test).

4. Boot loader initialization.

boot loaders

LILO (Linux loader) : not supporting multiple boot

Grub : GRand Unified Bootloader

bootProcess

                                                     Booting Process

masterBootRecord

                                                          Master boot record

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Chang Password from GUI

To change your password using GNOME,

Go to System

Preferences

About Me

and then click Password.

 

Change the password the first time you log in
Change it regularly thereafter
Select a password that is hard to guess

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Switching between virtual consoles and the graphical environment

A typical Linux system will run six virtual consoles and one graphical console

Server systems often have only virtual consoles
Desktops and workstations typically have both

Switch among virtual consoles by typing: Ctrl-Alt-F[1-6]

Access the graphical console by typing Ctrl- Alt-F7

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Basic Principles of Linux and Unix

1. Open boot : OS is ready to display

Testing and initializing the hardware.

Giving you access to a set of tools to program and to debug it.

2. In Linux Everything is treated as files, including hardware devices : Every device has a file corresponding to it

3. It contains small single purpose programs

4. Ability to chain programs together to perform complex tasks

5. Avoid captive user interface : Limited number of user interfaces to manage OS/Applications

6. Configuration dataset stored in text format

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Redhat Server Comparison







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Operating system structure

Operating system structure


A shell is a piece of software that provides an interface for users to an operating system which provides access to the services of a kernel.

the kernel is the central component of most computer operating systems; it is a bridge between applications and the actual data processing done at the hardware level.

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History & LINUX , UNIX distributions

linux

1969 – Unix ( An application created by Bell labs)

Read more here : http://en.wikipedia.org/wiki/History_of_Linux

Popular UNIX Flavors

Solaris – Sun Microsystems’ implementation, of which there are different kinds available: these are Solaris OS for SPARC platforms, Solaris OS for x86 platforms, and Trusted Solaris for both SPARC & x86 platforms; the latest version is Solaris 10 OS

AIX – short for Advanced Interactive eXecutive; IBM’s implementation, the latest release of which, is the AIX 5L version 5.2.

SCO UnixWare and OpenServer – are implementations derived from the original AT&T Unix® source code acquired by the Santa Cruz Operation Inc. from Novell, and later on bought by Caldera Systems; the latest versions are UnixWare 7.1.3 and OpenServer 5.0.7

HP-UX – short for Hewlett-Packard UniX; the latest version is the HP-UX 11i

Popular LINUX Flavors

CentOS, a distribution derived from the same sources used by Red Hat,maintained by a dedicated volunteer community of developers with both 100% Red Hat-compatible versions and an upgraded version that is not always 100% upstream compatible


Debian, a non-commercial distribution maintained by a volunteer developer community with a strong commitment to free software principles


Fedora, a community distribution sponsored by Red Hat

Gentoo, a distribution targeted at power users, known for its FreeBSD Ports-like automated system for compiling applications from source code

Knoppix, the first Live CD distribution to run completely from removable media without installation to a hard disk, derived from Debian

Mandriva, a Red Hat derivative popular in France and Brazil, today maintained by the French company of the same name.

OpenSUSE a community distribution mainly sponsored by Novell.

Red Hat Enterprise Linux, which is a derivative of Fedora, maintained and commercially supported by Red Hat.

SUSE Linux Enterprise, derived from openSUSE, maintained and commercially supported by Novell.


Ubuntu, a popular desktop and server distribution derived from Debian, maintained by Canonical Ltd..

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RHCE Exam Papers & About the OS

There are three papers for RHCE Examination, It’s as follows

RH033 – Red Hat Linux Essentials

RH133 - Red Hat Linux System Administration and RHCT

RH253 - Red Hat Linux Networking and. Security Administration

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Different os from Redhat

Server - Server Applications are integrated (Squid, Apache, Etc)

Client – Included client applications (Browser, IMs, Media players)

Fedora – Its a community version, bundled with latest applications

redhat editions