Big Data and Hadoop Training: Unix Commands


Slide 1: Unix Commands

Hello and welcome to lesson number 3 of Hadoop training by Simplilearn. Before we begin with this lesson let us first recap what we covered in the previous two lessons. In the first lesson we were introduced to the concept of Hadoop, after which, in lesson 2, we understood the Hadoop architecture. As Hadoop runs only in Unix/Linux environment, we are going to cover the basic Unix commands in this lesson. We are going to see the most useful Unix commands, which we will come across during this Hadoop training.

Before we begin, let us go through the agenda of this lesson.

Slide 2: Agenda

In this lesson we will cover some basic Unix commands to see how to create and delete a directory; move or rename a file or a directory; see the help on a command; and see the content of a file.

We will look into the basic Unix commands next.

Slide 3: Basic Unix Commands 1

All the Unix commands should be executed in a command shell. Commands are case sensitive and all commands should be terminated by carriage return character or Enter key. All the Unix commands given here as examples, are taken from the samples executed in Ubuntu running within VirtualBox (Unix running within Windows).

The first command we should try is pwd (abbreviate), which stands for print working directory. The pwd command outputs the name of the directory which we are currently located in. For example, typingpwd in the Desktop directory, will show /home/username/Desktop (read as “forward slash home forward slash username forward slash Desktop”).

In the highlighted section we can see that /home/jdutta (read as “forward slash home forward slash jdutta”) is the current directory generated by pwd command’s execution.

In the highlighted section, we can see a dollar ($) symbol which is populated before pwd command. The dollar symbol represents a prompt which means that now we can type the Unix command. It basically means that it is waiting for an input from the user.

We will continue our discussion of the basic Unix commands in the next slide.

Slide 4: Basic Unix Commands 2

Next important command we will discuss, is ls (read as “el es”) which stands for list. The ls command outputs a list of files in the current directory.