What is Linux Operating System?

Linux is one of the most reliable Unix-like computer Operating System (OS) under the model of free and an open-source software development and distribution. It is an editable Operating System. Introduced in the early 1990s, Linux manages and upkeeps everything from hardware like monitor, keyboard, other peripherals etc. to software applications as well.

What commands are used to delete files in Linux?

You can either delete a single file permanently or you can delete one or multiple files simultaneously. The two commands are:

The rm command:

This command is one of the most widely used command to delete single or multiple files simultaneously.

For example,

$ rm {file name}

The unlink command:

This command is used to permanently delete a file in Linux.

For example,

$ unlink {file name}

How to rename or move a file in Linux?

There are two ways to rename a file in Linux:

Using GUI file manager

Using command-line terminal.

We will learn to rename a file using two commands:

The mv command:

You require the knowledge of Bash Scripting to use this command. It is written as follows, for example:

$ mv file1.txt file2.txt

The rename command:

It is used to rename multiple files and it requires basic knowledge of regular expressions. This command renames files according to the specific perlexpr regular expression. For example,

rename [OPTIONS] perlexpr files

How to delete a directory in Linux?

The three commands used to remove a directory in Linux are:

rmdir:

This command is used to delete empty directories. The syntax used is:

$ rmdir dir1

rm:

This command is used to delete both empty and non-empty directories.

find:

This command allows you to search for directories on the basis of a given expression and then perform the action accordingly.

How to find a file in Linux?

To look up for a file in Linux, all you need to do is enter the find command to search up a file through its name or its extension. For example,

If you are looking up for a file called thisfile.txt, the following syntax is used:

find. -name thisfile.txt

If you are looking for all .jpg files in the /home directory, the following syntax is used:

find . -type f -empty

What is Kali Linux? How to install it?

Kali Linux is a free and the most popular Operating System (OS) with over 600 tools that are used for penetration testing and security analytics. It is mostly used by Cyber Security Experts.

The steps to install Kali Linux are given as follows:

Boot the system with CD/USB
Select your language of preference. Click ‘continue’.
Select your location.
Enter the hostname for the system.
Configure the network- enter the domain name.
Set up user account.
Set up user ID.
Configure the clock.
Choose your preferred partitioning method. ‘Use entire disc’ is the preferred method.
Select the partition disc.
Choose your partitioning scheme.
Analyze the options in the review page.
Configure the package manager.
Install the GRUB boot loader.
Click on ‘continue’ to reboot the system into Kali installation

What is Shell in Linux?

Shell reads your command in the Linux. It provides you with an interface to the Unix system and executes programs called commands. Technically, Shell is the Linux command line interpreter. The Borne Again Shell is the most commonly used shell used in Linux. For example,

the logout command logs out of the Linux terminal.

What is meant by the who command in Linux?

The who command gives you access to the list of users that are logged in to your Linux operating system at a given time. It also gives the following information:

Time of the last boot of the system
Current run level of the system

How to know the name and version of the Linux OS?

The OS version of Linux and the OS name can be found out by following the procedure given below:

Open the Bash shell (Terminal application).
Use ssh for remote server login.
Type any one of the following commands to find out Linux name and version:

cat /etc / os-release
lsb_release -a
hostnamectl

How to unzip a file on Linux?

A zip file could easily be unzipped using the GUI. Let’s learn how to extract a zip file using Ubuntu/ Debian:

1. Open the Files app and locate the directory where the zip file is present.

2. Go to the file which you want to unzip.

3. Right-click on the file and a drop-down menu will appear.

4. Click on the ‘Extract Here’ to unzip the file into the currently working directory.

5. Click on the ‘Extract To’ to unzip the file into some other directory.

Which command is used to copy a directory in Linux?

The cp command is used to copy files and directories on a Linux and Unix System. The general syntax used is:

cp [OPTIONS] SOURCE . . . DESTINATION

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