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Linux Technical Interview Question and Answers

A genuine collection of Interview Questions and Answers for Linux. Questions are based on basic and fundamental skills of Linux administration and operation and useful for both Experienced as well as Freshers.

 

What is Linux?

Linux is an operating system that was first introduced by Linus Torvalds based on UNIX and can run on different software platforms.

 

Which are the basic components of Linux?

The 3 basic components of Linux are;

  1. Kernel,
  2. System Library,
  3. System Utility.

 

What is the main difference between UNIX and Linux?

Unix is a propriety operating system from Bell Laboratories while Linux is a non-appropriate operating system free for the masses.

 

What is a Kernel in Linux?

 A kernel is generally a low-level system software whose main aim is to manage hardware resources to the users.

 

What is a BASH as used in Linux?

 Bourne again shell is represented by bin/sh and acts as the default system for the most system running Linux.

 

What is a shell?

A shell is the layer of programming that understands commands entered by a user.

 

What is a kernel file name?

Vmlinuz is the Linux Kernel executable since Linux supports Virtual memory.

 

What is the command used to delete a user out of the directory?

To delete a user together with the file directorate you use the userdel-r username command.

 

Where is the user password stored in?

The user password in Linux is stored in the etc/password which suggests the file is readable.

 

Where are the runs levels stored in?

The run levels start up on reboot and are usually stored in the /etc/rc.d folder.

 

Which are the default file systems of Linux?

The default file systems in Linux are Ext3 or Ext4 files which are the most modern version of the Ext file system.

 

Define BASH and state its meaning.

BASH means Short for Bourne Again Shell and its function is to combine all features from the original Bourne version to Shell.

 

Is it possible to use the ctrl+Alt+Del work in Linux?

The Key combination works, in that Unlike Windows it doesn’t give a boot confirmation message thus making a boot immediately.

 

Briefly describe the root account.

The root account acts as a system administrator account allowing full control of the system. On a root account, you can create and maintain user accounts and assigning of permissions in each account.

 

In Linux,which is the commnd used to find out how much memory is left ?

You can use the following command to find the current memory usage

  1. Free –m
  2. Vmstat
  3. Top
  4. htop

 

What are the symbolic links?

symbolic links perform the same functions as shortcuts in windows and they point out to files and directories.

 

How do you change permissions under Linux?

To change permissions using the chmod command as the system administrator or the owner to a file directorate. The + adds permission while – denies permission along with other letters. Example, chmod go+rw FILE2.TXT grants read and write to the file FILE2.TXT.

 

Which  names  are assigned to different serial ports in Linux?

In linux serial ports are identified as /dev/ttyS0 to /dev/ttyS7 .which are equivalent to COM1 to COM8 in windows.

 

What does an empty directory represent?

A nameless or empty directorate acts an attachment for other directories, files, drives, and devices.

 

Define a pwd command and give an example.

The pwd command is short for print Working directory command.

Example:PWD

Output :/home/user1/myDir

 

How do you terminate an ongoing process in Linux?

To terminate a process, use the kill command followed by the process id. To terminate all processes use kill 0.

 

Give one advantage of an open source

An open source allows one to distribute your software including source codes to anyone interested. Open source allows people to add features debug and detect errors in the source code.

 

What is the key difference between BASH and DOS?

DOS has a strict file naming system which is 8 character file name and a dot, 3 characters for an extension while BASH doesn’t follow any format.

 

How does case sensitive affect Commands in Linux?

Linux commands are case sensitive.  Entering a command using a different casing than it should result in a different output.

 

What is command grouping as used in Linux?

command grouping is the use of parentheses to group commands.

 

Write a command whose output displays all.txt files including its individual permissions.

ls -al * .txt

 

Which command can one use to find the status of a processor?

To find the status of a processor we use the following command. Ps UX

 

What does the term GNU stand for?

The abbreviation GNU stands for Gnu’s not Unix

 

What is the function of a Virtual Box?

A Virtual Box makes it possible to run both Linux and Windows simultaneously on the same machine.

 

What is the function of the Command Line Interface (CLI)?

Command line interface enables the user to type commands that instruct the computer to perform tasks.

 

Write a command that will show a list of files in your current directory on a Linux system.

ls The ls command displays the total list of files on a current director

 

Write a command that will display all the commands you have used in the past and current termination session.

history

 

How do you insert comments in CLI?

On command line Interface, comments are made by typing the # symbol just before the actual comment text

 

Write a Linux command to list hidden files.

To list hidden files you use the following command: ls -a

 

Write a command that will a file to a new destination

mv filename new file location

 

What does LILO stand for and whats its function?

Linux Loader acts as the boot loader for the Linux operating system .It is loaded in the main memory in order for it to be operational.

 

Which are the different vi editor modes?

The 3 different kinds of modes in Vi editors are; Command mode or regular mode, Edit mode and Replacement mode.

 

Write a command used for creating Directories in Linux

The following command is used in creating directories: mkdir [directoryname]

 

Write down a command used to remove a directory.

The command used to remove a directory is :  rmdir [diectoryname]

 

What is the function of the man command?

The man command serves the same purpose as HELP. Help on any command that you probably need assistance on.

Dhananjay Yadav

Dhananjay Yadav

A Computer Science graduate, a blogger, a web developer worked on various web technologies.