Redhat Linux-Installation

Installing Red Hat Enterprise Linux in Graphical Mode

Steps:

1.Boot your system from the CD your instructor will Provide. This will start Anaconda,the Red Hat Enterprise Linux installer.
2.Press ENTER at the boot:Prompt.
3.choose the appropriate language for your region.
4.choose the appropriate keyboard layout for your region.
5.choose NFS image for the installation method.
6.you will now be prompted to do some network configuration.Select Use dynamic IP configuration(BOOTP/DHCP). Deselect Enable IPV6 support.
7.Enter the following information to configure the installation source:

• NFS Server Name:192.168.0.254.

• Red Hat Enterprise Linux directory:/var/ftp/pub

8.At this point Anaconda will retrieve the necessary installation image and probe the system for its monitor and mouse type.when this is completed,you will be presented with a welcome screen.
Click Next.
9.Select Skip entering Installation Number and click Next.Confirm by clicking skip.
10.Anaconda next checks if red hat Enterprise Linux is already installed on this system.If yes, it will offer you the option to perform an upgrade instead of a fresh installation.
Choose Install Red Hat Enterprises Linux and click Next.
11.Select Remove Linux partitions on selected devices,Create default layout and Review and modify partitioning layout, then click Next.
12.Use the default Boot Loader settings unless the instructor advises otherwise. Do not create a Boot Loader password.
13.choose DHCP for networking and check the activate on boot check box.
14. Set the time zone as appropriate for your location;Implement UTC if the instructor suggests it.
15. Set the root password to redhat.
16. Use the default set of packages.
17. you Should now be at the About to install screen. Click Next to begin.
18.Track the Progress of filesystem formatting by switching to tty5(Ctrl-Alt-F5 will take you there;Ctrl-Alt-F6 will return you to the installer)
19. After the reboot following the installation, complete the initial set up tool;.Create a user account of your choice.Do not register the machine with Red Hat Network. Select No,I prefer to register at a later time followed by No thanks, I'll connect later.Select Enable Firewall when prompted to configure the firewall.Use the default values for all other settings.
2o. Once you have completed the installation and the newly-installed system has booted,log in as root and examine the following.

• /root/install.log
• /var/log/messages
• /var/log/dmesg

Silent Sound Technology

You are in a movie theater or noicy restaurent or a bus etc where there is lot of noice around is big issue while talking on a mobile phone. But in the future this problem is eliminated with ”silent sounds”, a new technology unveiled at the CeBIT fair,that transforms lip movements into a computer-generated voice for the listener at the other end of the phone.
Silent Sound’ technology aims to notice every movements of the lips and transform them into sounds, which could help people who lose voices to speak, and allow people to make silent calls without bothering others. Rather than making any sounds, your handset would decipher the movements your mouth makes by measuring muscle activity, then convert this into speech that the person on the other end of the call can hear. So, basically, it reads your lips.This technology also helping people who have lost their voice due to illness or accident to telling a trusted friend your PIN number over the phone without anyone eavesdropping — assuming no lip-readers are around.

Perl Array

Today we can learn some thing about Array in perl.

An array variable starts with an @ symbol.

DEFINING AN ARRAY:

@num=(1,2,3,4);

@str=(‘hi’,’hello’,hey’);

COMBINING OF ARRAY:

Two array can be combined easily in perl

For Eg:

1.pl:

@num=(1,2,3,4);

@str=(‘hi’,’hello’,hey’);

@combine=(@num,@str);

Print “@combine\n”;

o/p: 1 2 3 4 hi hello hey

Simplify:

While declaring string in array we no need to waste time by giving quotes for that special quoting function is there qw.

Eg:

2.pl:

@color=qw(black green white);

CREATING A LIST USING RANGE OPERATOR:

@num=(1..20);

Will have no from 1 to 100

@letter=(‘a’..’z’);

One Example for swaping of numbers.

Its very easy in perl

3.pl

($a,$b)=(1,2);

print "before swap\n";

print "a=$a\n";

print "b=$b\n";

print "after swap";

($a,$b)=($b,$a);

print "after swap\n";

print "a=$a\n";

print "b=$b\n";

o/p:

before swap

a=1

b=2

after swap

a=2

b=1

TO FIND END OF ARRAY:

Just declare $#array name

4.pl

@num=(1..20);

print $#num;

o/p:

19.

Index starts from 0.

NEW GALAXY
A team of scientists from the UK and the US has discovered a galaxy far away from us which is churning out stars 250 times faster than our Milky Way. The discovery of the galaxy, about 10 billion light years away from the earth, will help researchers understand how the Milky Way was formed.

Galaxy SMM J2135- 0102 has four distinct star- forming regions, each of which is 100 times brighter than Milky Way locations such as the Orion Nebula. The team which discovered the galaxy was led by scientists from the UK's Durham University.

It also included researchers from European Southern University and the Massachusetts based Harvard- Smithsonian Center for Astrophysics." The new galaxy is forming stars at about 250 suns per year. Our Milky Way is forming about two suns per year," lead scientist Mark Swinbank of Durham University said. Because of the time it takes light to reach the earth, the scientists observed the galaxy as it would have appeared 10 billion years ago - just three billion years after the Big Bang.

PERL INTRO

INRODUCTION TO PERL:
Perl stands for Practical Extraction and Reporting Language. Perl is a general-purpose, high level, interpreted and dynamic computer programming language with a vast number of uses. Perl was invented by Larry Wall, a linguist working as a systems administrator at NASA in 1987. Today Perl is found in varied applications such as finance, manufacturing, genetics, the military etc to process large data sets. Perl is used to be one of the most popular languages for developing web applications. At that time, Perl is used to write CGI scripts. Perl is very good and optimized for problems that handle 90% of text and 10% of other. Perl is best for short and small programs that can be entered and run on a single command line.
Perl run well on UNIX and Windows systems. If you develop Perl for UNIX system, it can be portable to Windows system as well.
Download and install ActivePerl
You first need to download ActivePerl the latest version from http://www.activestate.com/activeperl/ . You can also find the installation files for other systems and versions via following link http://www.activestate.com/activeperl/downloads/
To install ActivePerl just double click on the installation file. It will guide you through steps with options. Just make your own choices and click next.
To check you installation you can open command line through Run windows and type following command: perl –version or perl -v. If you installed Perl successfully, you will see the version and copyright information.
FIRST PERL PROGRAM
First, you open the Open Notepad or Notepad++ and type the following code:
1. #E:/usr/bin/perl
2. print "Hello World!\n";
You can save the Perl source code file with any name and extensions you want. Perl source code file should has extension *.pl or *.ple (Perl executable).
Running the program:
Go to cmd prompt-> type perl filename.pl
Let's look at the program in more details.
The first line of the program is a special comment. Comments in Perl program start from the pound sign (#) to the rest of line. There is no sign for block comment.
The second line starts with print statement followed by a string “Hello World” and then followed by a semi-comma. Every Perl statement has to be ended with a semi-comma (;).

VIRTUAL MACHINE INSTALLATION

In order to run VirtualBox on your machine, you need:
• Reasonably powerful x86 hardware. Any recent Intel or AMD processor should do.
• Memory. Depending on what guest operating systems you want to run, you will need at least 512 MB of RAM (but probably more, and the more the better). Basically, you will need whatever your host operating system needs to run comfortably, plus the amount that the guest operating system needs.
• Hard disk space. While VirtualBox itself is very lean (a typical installation will only need about 30 MB of hard disk space), the virtual machines will require fairly huge files on disk to represent their own hard disk storage. So, to install Windows XP, for example, you will need a file that will easily grow to several GB in size.

VIRTUAL MACHINE INSTALLATION
Step 1: After you installed the virtual box open the virtual machine wizard(All Programs->Sun Virtual Box) Click the “NEW” button.
Step 2: Provide the VN name(user defined) and select the OS type(For Eg., if you want to use Windows XP as your virtual os select Windows XP)
Step 3: Select Base Memory size. The Size should not be more than 50%. (Eg your RAM size is 1024 MB(1 GB) then memory size should not be more than 512 Mb i.e <512)
Step 4: Select Virtual Hard Disk(.vdi). If its not created in host OS follow the below steps.
Step 5: Select VHD(Virtual Hard Disk) type->Dynamic Storage is the preferable one.
Step 6: Select the VHD Location and Size
Step 7: Click Finish. Your VM has created.
Step 8: Before you Starting you VM review your settings.
Step 9: You can launch your VM

Message of the day

More than 12,000 laptops go missing at US airports a week!

Researchers consider that the first search engine was Archie, created in 1990 by Alan Emtage, a student at McGill University in Montreal, Canada.