15 Basic Linux Interview Questions with Answers (Entry-Level)

Linux is one of the most widely used operating systems in both personal and enterprise environments. Whether you’re aiming to become a system administrator, DevOps engineer, software developer, or IT professional, having a solid foundation in Linux is essential.

To support your learning and interview preparation, we’re excited to introduce a dedicated Linux Interview section on Tecmint, which will feature carefully selected Linux interview questions, along with detailed answers to help you prepare with confidence.

Every weekend, we’ll publish a new article in this section, starting from basic Linux questions and gradually moving toward more advanced topics. This initiative is one of the first of its kind among Linux-focused websites, and we’re committed to delivering high-quality, useful, and unique content.

Let’s get started with 15 basic Linux interview questions and answers to kick off the series.

Q1: What is the core of the Linux Operating System?

The core of the Linux operating system is the Kernel, which is the lowest level of the OS and acts as a bridge between the hardware and the software. It is responsible for managing system resources such as memory, CPU time, device drivers, and system calls.

The Linux Kernel is monolithic, meaning it includes the core system functions, device drivers, and file system management all within a single large block of code running in a single address space.

Q2: What Did Linus Torvalds Create?

Linus Torvalds created the Linux Kernel in 1991. It began as a hobby project while he was a student at the University of Helsinki, Finland. Initially inspired by MINIX (a Unix-like system for education), he created a free, open-source alternative.

Over time, the Linux Kernel evolved into the core of many operating systems, collectively referred to as Linux distributions (e.g., Ubuntu, Fedora, Debian).

Q3: Did Linus Torvalds Write Most of the Linux Kernel in C++?

No, this is incorrect. Linus Torvalds wrote most of the Linux Kernel in the C programming language, not C++. In fact, Linus has been publicly critical of using C++ in kernel development due to concerns about performance, complexity, and reliability.

The C language is preferred in kernel development because it provides low-level memory access, minimal runtime overhead, and maximum control over hardware resources.

Q4: Was Linux Initially Developed for Intel x86 Architecture, and Has It Been Ported to Other Platforms?

Yes, Linux was initially developed for the Intel x86 architecture (32-bit systems), but over the years, it has been successfully ported to a wide range of hardware architectures.

These include ARM, PowerPC, SPARC, MIPS, and even mainframes. Today, Linux runs on everything from smartphones and tablets to servers, supercomputers, routers, and embedded systems.

Q5: Is It Legal to Edit the Linux Kernel?

Yes, it is entirely legal to edit the Linux Kernel, as it is released under the GNU General Public License (GPL) version 2, which means it allows users to view, modify, and redistribute the source code freely, as long as any modifications are also made available under the same license.

This freedom is one of the reasons Linux has become so popular and widely adopted in various projects.

Q6: What is the Basic Difference Between UNIX and Linux?

UNIX is a proprietary operating system originally developed at AT&T’s Bell Labs in the 1970s. Linux, on the other hand, is a UNIX-like operating system that is free and open-source.

While UNIX systems are often used in commercial environments and have different variants (e.g., AIX, Solaris, HP-UX), Linux is a community-developed system that shares similar principles and design with UNIX but is not derived from UNIX code.

Key differences include:

Feature UNIX Linux
Licensing Proprietary Open-source (GNU General Public License)
Cost Usually requires purchasing a license Free
Hardware Often used on specialized hardware Supports a broad range of hardware devices

Q7: Is the Linux Operating System Virus-Free?

No operating system is completely virus-free, including Linux. However, Linux is considered more secure than many others due to its permission-based structure, user role separation, and large community of developers who actively maintain and patch vulnerabilities.

Additionally, Linux is less targeted by malware due to its smaller desktop market share compared to Windows. That said, administrators should still use security best practices and tools like firewalls, SELinux, and antivirus software.

Q8: What Type of Operating System is Linux?

Linux is a multi-user, multitasking, and multi-threaded operating system.

Specifically, it is a:

  • Unix-like OS
  • Open-source OS
  • Modular and monolithic Kernel-based OS

Linux is used as both a server OS and a desktop OS and supports features such as process scheduling, virtual memory, shared libraries, and dynamic loading.

Q9: What is the Syntax of a Linux Command?

The general syntax of a Linux command is:

command [options] [arguments]

For example:

ls -l /home/user

Here,

  • ls is the command (list directory contents).
  • -l is an option (long listing format).
  • /home/user is the argument (the directory to list).

Q10: What is a Linux Distribution?

A Linux distribution (or distro) is a complete operating system based on the Linux Kernel and includes system software, package managers, and often a graphical user interface (GUI).

Examples include Ubuntu, CentOS, Fedora, Arch Linux, and Debian. Each distribution serves different purposes and caters to different users from beginners to enterprise environments.

Q11: What are Runlevels in Linux?

Runlevels are predefined states of the machine in Unix-like systems that define what services are running.

Traditional SysV init systems used numbered runlevels such as:

  • 0 – Halt
  • 1 – Single-user mode
  • 3 – Multi-user mode (without GUI)
  • 5 – Multi-user mode with GUI
  • 6 – Reboot

Most modern Linux distributions (such as Fedora, CentOS 7+, Ubuntu 15.04+, and others) have replaced the SysV init system with systemd, which uses targets instead of runlevels for managing system states.

Here’s how systemd targets map to traditional runlevels:

Runlevel systemd Target Description
0 poweroff.target Shut down the system
1 rescue.target Single-user mode
3 multi-user.target Multi-user mode, CLI only
5 graphical.target Multi-user mode with GUI
6 reboot.target Reboot the system

Q12: What is the Difference Between Hard Links and Soft Links?

  • Hard Link: Points directly to the data on the disk (inode). If the original file is deleted, the hard link still works.
  • Soft Link (Symbolic Link): Acts like a shortcut. It points to the original file by path. If the original file is removed, the symbolic link becomes broken.

Q13: What is a Shell in Linux?

A shell is a command-line interface that allows users to interact with the operating system. It interprets user commands and passes them to the Kernel for execution.

Popular Linux shells include:

  • Bash (Bourne Again Shell)
  • Zsh (Z Shell)
  • Ksh (KornShell)
  • Tcsh (TENEX C Shell)

Q14: How Do You Check Memory Usage in Linux?

You can check memory usage using the following commands:

  • free -h: Displays used, free, and total memory.
  • top: Real-time view of system processes and memory usage.
  • vmstat: Reports memory, CPU, and I/O usage.
  • htop: Interactive process viewer (needs to be installed).

Q15: How is File Permission Represented in Linux?

File permissions in Linux are represented using three sets of attributes:

  • User (owner)
  • Group
  • Others

Each set includes permissions for:

  • Read (r)
  • Write (w)
  • Execute (x)

Example:

-rwxr-xr-- 1 user group 1234 Jan 1 12:00 file.txt

This means:

  • Owner has read, write, execute
  • Group has read, execute
  • Others have only read

You can change permissions using chmod and change ownership using chown.

Conclusion

Understanding the basics of Linux is crucial for many roles in modern IT environments. These questions cover foundational knowledge you’re likely to encounter in entry-level interviews.

As you progress, consider exploring more advanced topics such as process management, scripting, file systems, and networking in Linux.

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Ravi Saive
I'm Ravi Saive, an award-winning entrepreneur and founder of several successful 5-figure online businesses, including TecMint.com, GeeksMint.com, UbuntuMint.com, and the premium learning hub Pro.Tecmint.com.

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132 Comments

Leave a Reply
  1. Would I in Linux have access to ancient Greek, to characters with diacritics and to phonetic characters; not be inserting them via a Menu, but install them so that I can switch keyboard from English/European to Greek, and to English with diacritics (e.g. Sanskrit)?

    Reply
  2. I think it should be pointed out, regarding #3, that the number of lines of code in Linux changes — generally upward — with each kernel release, and no-doubt the numbers shown in the answer are now outdated, but no-doubt were true at the time this article was written.

    Reply
  3. Hi,

    Good article and helpful to beginner or who wants to recall their knowledge in linux.

    I have observed the two things which needs to be corrected.

    1. Spelling of Linux on starting of answer of question #2.
    2. Do needful changes in given options of question #10.

    Thanks in advance!

    Reply
    • @Sumit,

      Thanks for finding this article useful, but do the spelling ‘Linus’ is correct – he is Linus Torvalds creator of Linux.

      Reply
  4. Hello
    Does anyone know this error?

    error while loading shared libraries: libX11-xcb.so.1: can not open shared object file: No such file or directory

    Reply
  5. Question No.2 seems to be wrong.

    Q.2: What Linus Torvalds Created?

    Fedora
    Slackware
    Debian
    Gentoo
    Linux

    Answer : Linus Torvalds created Linux, which is the kernel (heart) of all of the above Operating System and all other Linux Operating System.

    Reply
  6. I have installed Windows 7 on my laptop.
    I have installed Virtual Box and in that installed RHEL 5 and its working fine.
    When I installed RHEL 7 on that, ifconfig command is not working.
    What is the reason, could you please help me out here.

    Reply
  7. can some one help me

    while i was creating the empty files using “touch” command it is creating like this

    [root@srikanth ~/nagios]# touch file{1..10}
    [root@srikanth ~/nagios]#
    [root@srikanth ~/nagios]# ls
    file1..10
    [root@srikanth ~/nagios]#

    Reply
    • @Srikanth,
      I’ve tried same command and it’s works fine, here is the output of the command.

      # touch file{1..10}
      # $ ls
      file1  file10  file2  file3  file4  file5  file6  file7  file8  file9
      
      # ls -l
      total 0
      -rw-r--r-- 1 tecmint tecmint 0 Nov 10 11:33 file1
      -rw-r--r-- 1 tecmint tecmint 0 Nov 10 11:33 file10
      -rw-r--r-- 1 tecmint tecmint 0 Nov 10 11:33 file2
      -rw-r--r-- 1 tecmint tecmint 0 Nov 10 11:33 file3
      -rw-r--r-- 1 tecmint tecmint 0 Nov 10 11:33 file4
      -rw-r--r-- 1 tecmint tecmint 0 Nov 10 11:33 file5
      -rw-r--r-- 1 tecmint tecmint 0 Nov 10 11:33 file6
      -rw-r--r-- 1 tecmint tecmint 0 Nov 10 11:33 file7
      -rw-r--r-- 1 tecmint tecmint 0 Nov 10 11:33 file8
      -rw-r--r-- 1 tecmint tecmint 0 Nov 10 11:33 file9
      
      Reply
  8. I am kumar..I will atten the interview Linux how to prepare the interview..I have completed 2 rounds last one round technical interview ..pls give a successtion…

    Reply
  9. Hello, first of all great article I’m studying for an interview and this has been helpful. It appears to me that question number 10 has the correct answer listed twice.

    Best regards.

    Reply
  10. Beautiful article and complete website too.. gives basic idea i never even though of besides executing few basic commands. I am new to Linux. I will surly visit all articles one by one..

    Reply
  11. Thanks Sir, for the useful info, ppl like you are helpful for the guys like us, u r work is appreciated and looking more forward for the knowledge .

    Reply
  12. hello sir, this is awesome, i’m just near to complete my RHCE exam,n i know,this basic knowledge will help me strongly in interview.keep it up sir.

    Reply
    • Dear Harish,
      we are coming with Interview Article every Saturday (except a few exception).
      Keep connected to Tecmint for that.

      Reply
  13. HI.Avishek Kumar..

    Hope so u doing well. Could share me the Interview questions docs for WIndows & Linux. I am beginner for linux & i have experience with windows domain. Could share me the docs.

    Plz connect me on this mob no for our further conversation(8792830783).

    Reply
    • Dear vssmanian,
      As said earlier, It is not possible to send each of our readers the article in person, on their personal IDs. Moreover it is against our Policy.

      You can subscribe us and keep visiting Tecmint every now and then for more such questions.

      Reply
  14. Hi Avishek,

    Very nice article and interesting and knowledgeable for learners of Linux and very useful for interviews. Keep it up,

    Reply
  15. Hello Avishek,

    I am Linux Enthusiast and MCA. New in the field of Linux. It’s a great beginning for me. Excellent Basic things covered.

    Thanks

    Reply
    • Dear Harshal kulkarni,
      Thanks for your feedback.
      We (Tecmint Team) is happy to know, our writing is helping our readers, followers and fans.

      Reply
  16. Good format to spread knowledge: very simple, helpful and clear 4 all.. …..plz post experience question
    shukriya …

    Reply
  17. Hi Avishek,
    This is Eshwaran i want know basic linux system admin question ,my intrest linux admin,but i dont have experience linux. also i am looking video linux admin like CBT Nugget.I have experience 3 years but windows platform,can guide me .share linux system admin question and answer….
    my email id:[email protected],7760680717

    Reply
    • Dear Kumar, Thanks for the feedback.

      You should choose your carrier based upon area of Interest and not Field. There is no salary Limit for a deserving person in any field of the world.

      So choose your carrier on your area of expertise and interest.

      Reply
  18. this is awesome,i’m just near to complete my exam,n i know,this basic knowledge will help me strongly in interview.keep it up sir.

    Reply
    • @ DANISH,
      It would be very difficult for us to send Interview Questions/Answer in Person. Please search our website as keep connected. If you find any topic/subject we have not touched, we will be happy to help.

      Reply
  19. SUPER AM A FRESHER LEARNING LINUX PROVIDE MORE AND MORE INTERVIEW QUESTIONSSSSS…..

    PROVIDE TROUBLESHOOTING INTERVIEW QUESTIONSSSS

    Reply
    • Thanks @ PURUSHOTHAM, we will be providing Troubleshooting interview questions in our future post. Although we keep a few troubleshooting question relating to topic, in the post.
      Keep connected.

      Reply
    • Hi

      You content is very useful.

      I am having an interview next week on Linux and SQL

      I am fresher and i want to know some questions based on linux and SQL for fresher level for my next interview purpose . If you could help on that i’ll be very greatful to you for this.

      Waiting for positive reply asap.

      my Mail id : [email protected]
      Ph no. 9873734035

      Reply
      • Thanks @ Danish.
        Our sole purpose is to provide anything and everything related to Linux, in as much simple way as possible and comments of such kind, confirms we are on right Track.

        Reply
  20. About Q.10: Syntax of any Linux command is, I don’t understand why having square brackets [] will make any difference among those answers. Could you please give me some examples to clarify?

    Reply
    • Let me take a stab at it. In documentation, [brackets] are used to denote that something is optional. In this sense, command [options] [arguments] is the correct choice as you can often just run the command.

      I would argue that the focus on the [brackets] conveys the wrong intention. The focus turns the question into more “Do you know how to read documentation for a command?” rather than “Do you know options and arguments cannot precede the command?”

      Also, command [arguments] [options] is just as valid. ls -l /home/user = ls /home/user -l

      Reply
      • hye avishek, im beginner to use Linux, please teach me ad guide me how to use it and master it, any guide which understand very fast..thanks

        Reply
        • Dear yogi,
          keep going through each of our articles already on Tecmint as well as new articles to come, you will learn a lot.

          Reply
      • Hi sir, i am a beginner in linux OS, i would like to do Redhat certified system Administrator also pass the exam of corse, so can you me what type book do i need or advice me anything i can do to pass my exam. I really want to take all certificates in Redhat linux in the future., please help me. Thank you in advance.

        Reply

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