Introduction to Linux

What is Linux?

• Linux is an OS.• OS is software layer that is between the

hardware and software(application). OS is what allows the software to talk to the hardware. e.g Print a file, write a file , etc.

• Created between 1991 to 1994 by Linus Trovalds.

What is Linux?

• Linux is not Unix(Similar sounding …ux).• 1990s Unix was a paid OS so was Microsoft• Linux created it from scratch as he wanted a

free open source OS.

Linux Distro

• Since code was open source people started creating their own flavors of Linux.

• Various versions of linux created are called distros . E,g Red Hat, Ubuntu, Google Andriod(mobile phones) are different distros.

• While selecting what distro to use u must decide what u want your computer to do before you install your OS.

Linux Distro

• In Linux every distro is built to do things in a certain way.

• Few Distros: Trustix Linux (most secure-solid brick ) or Ubuntu for Desktop(Normal use) or Red Hat for Enterprise or DSL(Damm Small Linux) only 53 MB .

Open Source License

• Does open source software mean free Software?

Open Source License• It’s a wrong idea. • Open source software means that the

programmers provide you with the code so that you can see how the program was written.

• Lets see how these vendors get paid. There are four different ways.

Open Source License• Lets see how these vendors get paid. There are

four different ways. Software is given utterly free(Mysql model) but when

you need help their services need to be paid.(e.g training, troubleshooting, etc).

Software is free for personal and non-commercial use. As soon as you use it for commercial purpose you have to pay. You can set up a network server in a lab but as soon as you used it in a production environment you have to pay a licensing fee which can be a huge amount.

Open Source License• Contd.

Software is sold as everyone sells it and the difference from that with windows is you can still see the source code. However you don’t have right to modify the code(copyright issue).

Software is given for free. However the license states in order to use the software you have to pay a reoccurring contract( e,g to use redhat pay 100$ to 1000$ as annual fees…subscription contract).

The Shell• It is the screen you use to interact with the OS. • Windows is GUI shell or LUI shell(DOS

prompt) while in Linux mostly LUI shell is used which is more powerful shell.

ROOT

• Biggest concept of Linux.• Highest level user you can be. It is like an

administrator in windows.• If you log in as root you can do anything.• Linux root is represented as \ while in

windows it is C:/. It is where the OS resides.

Capitalization

• Upper case or Lower case letters.• Windows doesn’t care except for passwords.

i.e Home=home=HoMe=hoME.• Linux was created by and for computer

professionals, computer scientists and technical people. Here home dir is different from Home dir. All letters are represented as ASCII text and H is a different character then that of h.

Server vs Desktop

• Main difference: Server version is a striped down version of the Desktop version.

• It is because it is assumed that if you want to install a server you know what you want from it. There will be no tools or GUI. You have to downlaod and install whatever you require.

• Best install desktop version if you are new to Linux because it has GUI.

Why use Linux?

• Linux is good for something and crap for something.

• As a desktop OS it is slow and freezes up frequently.

• Very good for server functionality. It is a rock solid once installed it will just keep on running without any flaws.