Top Linux Admin Interview Questions for Fresher and Experienced Developers

If you want to work as a Linux System Admin, you should be aware of the types of Linux admin interview questions that will be asked during your technical interview. The competition in Linux system admin interviews is becoming increasingly fierce, and you must be an expert to land a good job.

Linux is a free and open-source operating system that is similar to Unix. This article provides basic and advanced Linux admin interview questions for both new and experienced developers to help you prepare for your interview.

If you are preparing for a tech interview, check out our technical interview checklist, interview questions page, and salary negotiation e-book to get interview-ready! Also, read Amazon Coding Interview Questions, Facebook Coding Interview Questions to Nail Your Next Interview, and Google Coding Interview Questions for specific insights and guidance on Coding interview preparation.

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This article will cover:

• Linux Admin Interview Questions and Answers for Freshers
• Linux Admin Interview Questions and Answers for Experienced Developers
• Sample Linux Admin Job Interview Questions for Practice
• FAQs on Linux Admin Interview Questions

Linux Admin Interview Questions and Answers for Freshers

Q1. What is a Root Account, and what is its purpose?

A system administrator account that exists by default when installing LINUX is referred to as a root account. A root account helps us:

• Apply complete control over the system.
• Create and maintain several user accounts
• Assign appropriate permissions to each user account.

Q2. In Linux, what do we need to set up Password Aging?

To set up password ageing in Linux, we need the following:

• The change command, which allows the system administrators in Linux to enforce password aging. Change is used to change the time duration between compulsory password changes.
• The file /etc/login.defs, which is responsible for handling system-wide configuration. It can be edited for:

PASS_MAX_DAYS, which represents the maximum number of days for which a password may be valid.

PASS_MIN_DAYS, which represents the minimum number of days that need to pass before you can change your password again.

PASS_WARN_AGE, which represents the number of days after which a warning is given before the current password expires.

Q3. Define symbolic links.

Symbolic links redirect to another file somewhere in the file system, but the target file does not store any data. So if the target file is deleted, the link to that file is removed, but not the file.

Q4. What are Daemons?

Background processes that accept requests for service from other computers are called Daemons.

Q5. What is BASH?

Bourne Again Shell, or BASH, is a command language interpreter written by Brian Fox. It is similar to Bourne Shell and can be used in place of it. BASH, however, includes some additional features, and on many Linux, installations serve as the default user shell. It can run in the terminal window and read commands from shell scripts.

Sample Linux Admin Interview Questions and Answers for Experienced Developers

Q1. What are the various kinds of permission under Linux, and what do they represent?

There are three types of permissions in Linux:

1. The Read permission: Allows users to list the directory and read the files.
2. The Write permission: Allows users to write to a file and add new files to the directory.
3. The Execute permission: Allows users to run a file and lookup for a specific file within a directory.

Q2. Who can change permissions in Linux? How can permissions be changed in Linux?

The owner of the file, the owner of the directory, and a system administrator can change or grant permission to others with the help of the chmod command. The order goes:

• Chmod command
• Permission’s receivers (a for all, u for user, g for group, and o for others)
• Permission granted or denied
• Type of permission (r for read, x for execute, and w for write)
• File name

The syntax then becomes:

chmod permissionReceivers +typesOfPermissions fileName

For example:

chmod gu+rw exampleFile.txt

will grant read permission and write permission to the group and the user for the file exampleFile.

Q3. What are the basic components of Linux, and how many types of Shells exist in it?

The basic components of Linux are Kernel, Shell, GUI, System Utilities, and Application Programs.

Linux has five types of Shells: C Shell or csh, Korn Shell or ksh, Z Shell or Zsh, Bourne Again Shell or bash, and Friendly Interactive Shell or Fish.

Sample Linux Admin Job Interview Questions for Practice

Here are some sample Linux Admin interview questions for fresher and experienced developers. Practice these questions to nail your tech interview:

Linux Admin Basic Interview Questions

1. Define and describe:

1. Linux
2. History of Linux
3. Linux Kernel
4. BASH
5. LILO
6. LVM
7. CLI
8. GUI
9. Swap Space
10. Environmental variables
11. Symbolic links
12. Hard links
13. Redirection
14. Daemons
15. Root account
16. Virtual desktop
17. Inode
18. Process id
19. Process states
20. Sar
21. Umask
22. Puppet Server
23. Load Average

1. How would you check memory and CPU stats?
2. How would you create a partition on a raw disk?
3. Where are the Sar logs stored, and what information does Sar provide?
4. What’s the location of kernel modules?
5. What are the advantages and disadvantages of Open Source?
6. Discuss the Process Management System Calls in Linux.
7. Elaborate on the File Permission groups in Linux.
8. How would you increase the size of an LVM partition?
9. How would you decrease the size of an LVM partition?
10. Discuss the features of the Linux OS.
11. What do you know about the invention and the history of Linux?
12. Describe the core of the Linux OS?
13. What are the advantages and disadvantages of open source?
14. How would you set umask for a user permanently?
15. How will you open a command prompt when you’re issuing a command?
16. Explain all the file permissions types in Linux?
17. How would you boot Rocky Linux, RHEL, and CentOS in Single User Mode
18. Name and describe the types of Shells in Linux?
19. Describe the basic components of Linux OS.
20. How would you share a directory using nfs?
21. Explain the different modes in the vi editor?
22. How can we check and mount NFS shares?
23. Discuss file systems and file system types in Linux.

Linux Admin Commands Interview Questions

1. What are the following commands in Linux, and what do they do:

1. ls command
2. tail command
3. grep command
4. ps command
5. env command
6. top command
7. netstat command
8. lsof command
9. chmod command
10. chown command
11. cp command
12. mkdir command
13. rmdir command
14. tail command
15. cat command
16. netstat command
17. lsof command
18. df command
19. du command

1. In Linux, how would you remove a file or a directory from a system?
2. Where are Ansible ad-hoc commands used, and how?
3. How would you find all the files under /var with a size greater than 300 MB?
4. How do you exit from the vi editor?
5. How will you delete data from a file in the vi editor?
6. Name some Linux-to-file content commands.
7. Name the command needed for signing requested certificates in a Puppet Server.

Linux Admin Interview Questions for Experienced Developers

1. Name the default ports used for:

1. SMTP
2. Squid
3. FTP
4. DNS
5. SSH
6. DHCP

1. Describe the following and why they’re needed in Linux:

1. LVM
2. Umask
3. Network bonding
4. Modes of network bonding

1. How would you do the following in Linux:

1. Set the mask permanently for any user
2. Lock a user account in Linux
3. Change the default run level in Linux
4. Share a directory using NFS

1. How would you check:

1. The status of the bond interface
2. Default route and routing table
3. Which ports are listening in your Linux Server

1. Name the default data directory for docker containers.
2. Describe manifests in Puppet.
3. How can we find the WWN numbers of HBA cards in a Linux Server?
4. Name some Linux distributors or Distros and describe their usage.
5. How can we add and change Kernel parameters?
6. What’s the need, and what are some advantages of LINUX?
7. What are internal and external commands?
8. State some features of the Linux OS.
9. Differentiate between:

1. BASH and DOS
2. Docker and Podman
3. Linux and Unix

1. Describe the following in Linux:

1. PIPE
2. Zombie process
3. Stateless Linux Server

1. What’s the use of Ctrl+Alt+Del in Linux?
2. Is Linux more secure in comparison to other operating systems? If yes, why?
3. Explain the communication between a parent and child process.
4. How would you upgrade Kernel in Linux?
5. How can we scan newly assigned luns on the Linux box without rebooting?

We hope that this list of top Linux Admin interview questions and answers will assist you in preparing for your coding interview. You can prepare your answers in advance by practicing the sample interview questions provided in this article. This will prepare you to effectively communicate your solutions and decisions to your interviewer.

FAQs on Linux Admin Interview Questions

Q1. What do Linux admins do?

Linux System Administrators take care of systems running on Linux OS. They ensure systems are updated as technologies change, oversee the installation of new software, grant permissions, and train users.

Q2. What are some of the main administrative tasks a Linux Admin should easily do?

As a Linux admin, some main responsibilities you’ll have are: Installing and setting up Linux systems/servers for team-wide or organization-wide deployment. Developing servers and working with individual users. Ensuring the system’s reliability, speed, and performance. Answering questions related to setup and installation. A Linux admin should do all these tasks efficiently.

Q3. What should a Linux administrator know?

Linux administrators should know SQL, VI editor, hardware setup and troubleshooting, user account management, backup, restore, network traffic packet capture, network switches, network routers, and firewalls.

Q4. What is Kernel?

Kernel, also known as low-level system software, is the first program that loads when a computer starts. It is the main component of Linux that serves as a resource managing link between hardware and software. It mainly manages hardware resources for users and provides an interface for user-level interaction.

Q5. What is swap space?

A space on a hard disk used when the RAM is full is called swap space. It is a substitute for physical memory or an extension of RAM. It mainly substitutes disk space for RAM when the real RAM doesn’t have sufficient space to hold all the programs running, and more space is required.

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