Linux is one of the most preferred operating systems in the world. Why? Because it makes it easy to perform operational tasks in a simple and systematic manner for the companies. Due to its popularity 1 of the 3 companies is acquiring this technology for their working environment.
This is hyping the demand for Linux professionals in companies with good skills in maintaining the working environment with Linux Enterprise. If you are a professional who wants to begin your career as a Linux Professional in the IT Sector, you can definitely go through this amazing article. What are we waiting for? Let’s get started!
20+ Linux Interview Questions and Answers
- What is Linux?
Because of its stability and security, Linux is an open-source operating system that is based on Unix and is widely used. It provides power to a wide range of gadgets, including embedded systems, smartphones, servers, and supercomputers.
2. Explain the basic features of the Linux OS.
Linux is a well-liked and adaptable operating system because of a few essential features:
- Open Source,
- Multitasking,
- Multiuser,
- Security,
- Stability and Reliability,
- Portability,
- File System Support,
- Networking,
- Shell/Command-Line Interface, and
- Package Management.
3. What are the major differences between Linux and Windows?
The following are the main distinctions between Linux and Windows:
- Open Source vs. Proprietary:
- Linux: Because Linux is open-source, anyone can view, alter, and distribute it without restriction.
- Windows: Microsoft created Windows, a proprietary software whose source code is not accessible to the general public.
- Cost:
- Linux: For use and download, the majority of Linux distributions are free.
- Windows: To use Windows, you must purchase a license.
- User Interface:
- Linux: It provides a choice of desktop environments (such as GNOME, KDE, and XFCE) so that users can personalize their interface.
- Windows: has a less customizable user interface than Linux and is more consistent overall.
- Command-Line Interface:
- Linux: a strong focus on using powerful shells like Bash with the command-line interface (CLI).
- Windows: utilizes Command Prompt and PowerShell, but a lot of users prefer to use the graphical user interface (GUI).
- Software Availability:
- Linux: In comparison to Windows, there is a larger selection of open-source software but less commercial software available.
- Windows: broad support for commercial software, particularly for applications used in gaming and business.
- File System:
- Linux: supports multiple file systems, including Btrfs, XFS, and ext4.
- Windows: mostly makes use of the FAT and NTFS file systems.
- Security:
- Linux: Because of its smaller user base and permission-based system, it is generally regarded as more secure.
- Windows: Although viruses and malware target it more frequently, security has significantly improved over time.
- Performance:
- Linux: renowned for its performance and efficiency, particularly with older hardware.
- Windows: may operate more slowly and with greater resource requirements on older or weaker hardware.
- Support and Community:
- Linux: features a sizable, vibrant community as well as a number of support forums. Enterprise distributions are eligible for commercial support.
- Windows: provides a multitude of third-party support options in addition to official support from Microsoft.
- Updates and Upgrades:
- Linux: Rolling releases are made possible by frequent and frequently user-controlled updates.
- Windows: Microsoft is in charge of managing updates; significant updates and security patches are released on a regular basis.
4. What is Linux and what are its core components?
Open-source Linux is renowned for its dependability, security, and adaptability to a wide range of devices. The fundamental parts of Linux consist of:
- Kernel,
- System Libraries,
- System Utility Programs,
- Shell, and
- File System.
5. Who invented Linux? Explain the history of Linux.
Linus Torvalds developed Linux in 1991 as a free and open-source replacement for Unix. It quickly became popular among developers and changed as a result of input from the worldwide community.
Many different types of systems, including embedded devices, smartphones, servers, and supercomputers, are powered by Linux these days.
6. How to prepare for a Linux admin interview?
Review essential Linux commands, concepts, and system administration tasks to be ready for a Linux administrator interview. You should also practice troubleshooting common problems.
Additionally, become hands-on with various Linux distributions and acquaint yourself with tools such as network configuration, cron jobs, and shell scripting.
7. Differentiate between a Linux kernel and a Linux distribution (distro).
The following are the five main distinctions between a Linux distribution (distro) and a Linux kernel:
- Definition:
- Linux Kernel: the central part of the Linux operating system, in charge of controlling system resources, hardware, and software-hardware communication.
- Linux Distribution: a full operating system, comprising package management systems, apps, and system utilities, based on the Linux kernel.
- Components:
- Linux Kernel: includes drivers, low-level system code, and essential features like file systems, memory management, and process control.
- Linux Distribution: consists of the Linux kernel plus extra applications, libraries, system tools, and graphical user interfaces.
- Development:
- Linux Kernel: The Linux community, led by Linus Torvalds, develops and maintains the system.
- Linux Distribution: developed and kept up to date by different groups or communities (such as Fedora by Red Hat and Ubuntu by Canonical), integrating additional software and the Linux kernel.
- Functionality:
- Linux Kernel: gives an operating system the basic functions it needs to function, like controlling hardware interactions and carrying out processes.
- Linux Distribution: offers an intuitive interface, a ready-to-use system, and pre-installed utilities, applications, and package managers for simple updates and installation.
- Usage:
- Linux Kernel: Although it can be utilized independently in a variety of systems or embedded devices, it is usually not intuitive when used alone.
- Linux Distribution: offering a comprehensive, useful, and user-friendly operating system with graphical interfaces and large software repositories, tailored for servers and end users.
8. Explain the concept of shells in Linux and list some common shells.
A shell in Linux is a type of command-line interpreter that gives users a way to communicate with the operating system. It takes commands from the user, decodes them, and then performs the actions. Moreover, system administration, automation, and scripting can be done with shells.
Common shells in Linux:
- Bash (Bourne Again Shell),
- Zsh (Z Shell),
- Fish (Friendly Interactive Shell),
- Ksh (Korn Shell), and
- Tcsh (TENEX C Shell).
9. How does the file system hierarchy work in Linux?
Beginning with the root directory (/), the file system hierarchy in Linux arranges files and directories in a structured fashion. Here’s a quick rundown of how it functions:
- Root Directory (/): the highest directory in the hierarchy of the file system, holding all other directories and files.
- Basic Structure:
- /bin,
- /boot,
- /dev,
- /etc,
- /home,
- /lib and /lib64,
- /media and /mnt,
- /opt,
- /proc,
- /root,
- /sbin,
- /tmp,
- /usr, and
- /var.
- Mount Points: folders to which file systems are mounted or attached, incorporating them into the global file system structure.
- Symbolic Links: Pointers to files or directories elsewhere in the file system, giving it flexibility and structure.
10. Describe the difference between hard links and symbolic links (symlinks).
The following are the distinctions between symbolic links, or symlinks, and hard links
- Definition:
- Hard Link: A directory entry that points straight to a file’s actual location on disk is known as a hard link. In essence, it generates several directory entries that all point to the same inode, which is a data structure that represents a file.
- Symbolic Link (Symlink): A unique kind of file known as a symbolic link uses the pathname of another file or directory as a pointer. It serves as a shortcut or pointer to the intended file or directory.
- File System Level:
- Hard Link: requires the target file to be on the same file system as the link itself and operates at the file system level.
- Symbolic Link: functions at the name resolution level and has the ability to link to nonexistent targets as well as files or directories located on various file systems.
- Behavior with File Deletion:
- Hard Link: As long as there is at least one hard link pointing to the inode, the hard link will still point to the same data on the disk even if the original file is removed.
- Symbolic Link: A symbolic link that points to an undefined destination becomes broken (dangling symlink) if the original file or directory is removed or moved.
- Size and Properties:
- Hard Link: since it points directly to the inode, it appears as an extra directory entry with the same size and permissions as the original file.
- Symbolic Link: appears as a tiny file with the target file or directory path, but the size and permissions are different from the original target.
- Usage:
- Hard Link: Often used for version control or keeping references to significant files, this technique creates multiple references to the same file while conserving disk space.
- Symbolic Link: used to link across different locations or file systems, create aliases or shortcuts to files and directories, and enable flexible file management.
11. What are some essential Linux user management commands (e.g., add, delete, modify users)?
The following are some crucial commands for managing users in Linux:
- useradd: creates a fresh user account in the database.
Example: ‘sudo useradd -m username’
- userdel: removes a user from the database.
Example: ‘sudo userdel username’
- usermod: alters an existing user account by altering its shell, home directory, or username, for example.
Example: ‘sudo usermod -d /new/home/dir username’
- passwd: alters the password for a user.
Example: ‘sudo passwd username’
- groupadd: forms a fresh group.
Example: ‘sudo groupadd groupname’
- groupdel: eliminates a group.
Example: ‘sudo groupdel groupname’
- usermod -aG: incorporates a user into an additional group.
Example: ‘sudo usermod -aG groupname username’
- groups: shows the groups to which a user belongs.
Example: ‘groups username’
- id: shows the IDs of users and groups.
Example: ‘id username’
- chage: modifies the user’s password expiration details.
Example: ‘sudo chage -E 2025-12-31 username’
12. How would you navigate the Linux directory structure using the command line?
The following commands can be used in a terminal to navigate the Linux directory structure:
- pwd: Print the current working directory.
- ls: List directory contents.
- cd: Change directory.
- mkdir: Make directories.
- rmdir: Remove empty directories.
- cp: Copy files or directories.
- mv: Move or rename files or directories.
- rm: Remove files or directories.
- find: Search for files or directories.
- locate: Find files by name.
- grep: Search for text within files.
- tree: Display the directory structure as a tree.
13. Explain the functionality of commonly used commands like ls, cd, cp, mv, and rm.
The following are the tasks that the commands are handling:
- cd: Change directory.
- cp: Copy files or directories.
- mv: Move or rename files or directories.
- rm: Remove files or directories.
14. How can you view and manage system processes in Linux?
Linux commands such as ‘ps’ (to list processes), ‘top’ (to display dynamic process information), and ‘kill’ (to terminate processes by ID or name) can be used to view and manage system processes. For administrative tasks like terminating processes that are not owned by you, use the ‘sudo’ command.
15. What are process states in Linux?
Linux processes can be in a variety of states, such as:
- Running (R): Either instructions are being carried out by the process, or it is waiting for CPU time.
- Waiting (S): The procedure is waiting for something to happen or for a resource to show up.
- Stopped (T): The process has been terminated, typically as a result of getting a SIGSTOP or SIGTSTP signal.
- Zombie (Z): Despite having finished running, the process remains listed in the process table, waiting for the parent process to read its exit status.
- Uninterruptible Sleep (D): The process is waiting for a signal-uninterruptible resource, usually I/O.
- Traced or Stopped (X): The process is halted or traced (used for debugging).
16. What is a Linux kernel?
The central component of the Linux operating system is the Linux kernel, which also facilitates communication between software and hardware applications and manages system resources like CPU, memory, and devices.
It offers necessary features like file system handling, device drivers, and process management.
17. How would you check disk space usage and manage partitions in Linux?
To manage partitions and verify disk space usage in Linux:
- Check Disk Space:
Use the ‘df’ command to display disk space usage:
df -h # Shows disk space in a human-readable format
- Manage Partitions:
Use the ‘fdisk’ or ‘parted’ command to manage partitions:
Example with fdisk:
sudo fdisk /dev/sda # Start fdisk for /dev/sda device
Example with ‘parted’:
sudo parted /dev/sda # Start parted for /dev/sda device
18. Explain the concept of packages and package management in Linux distributions.
Linux packages are collections of software programs or libraries that are designed to make installation, updating, and uninstalling them simple. Package management systems handle dependencies, guarantee software compatibility, and offer centralized repositories for effective distribution and maintenance of software packages across Linux distributions.
Examples of these systems are APT (Advanced Package Tool) in Debian-based systems and YUM (Yellowdog Updater, Modified) in Red Hat-based systems.
19. What is the difference between .rpm and .deb package formats?
Red Hat-based Linux distributions (like Fedora and CentOS) use the.rpm package format, whereas Debian-based distributions (like Ubuntu and Debian) use the.deb package format.
20. How would you install and remove software packages using a package manager?
Use ‘sudo yum install package_name’ (for Red Hat-based systems) or ‘sudo apt-get install package_name’ (for Debian-based systems) to install software packages.
Use either ‘sudo yum remove package_name’ or ‘sudo apt-get remove package_name’ to remove it.
21. Explain how to schedule tasks using cron jobs.
In Linux, you can use cron jobs to schedule tasks:
- Edit Cron Jobs: To edit the user’s crontab file, which contains a list of scheduled tasks, type ‘crontab -e’.
Example: ‘crontab -e’
- Define Schedule: Use the cron syntax (‘* * * * *’ for minute, hour, day, month, and day of the week) to specify the schedule.
Example: ‘* * * * * /path/to/command’
- Save and Exit: Make edits to the crontab file, and the task will be automatically scheduled to run at the designated intervals.
22. Describe basic troubleshooting techniques for common Linux issues.
Here are some fundamental methods for resolving typical Linux problems:
- Check Logs,
- Restart Services,
- Check Disk Space,
- Verify Network Connectivity,
- Update and Upgrade,
- Check Permissions,
- Test Hardware,
- Review Configuration Files,
- Use Debugging Tools, and
- Consult Documentation & Community.
23. What are some popular Linux distributions for desktops and servers?
Popular Linux distributions are available for desktops and servers in multiple varieties. Here are a few popular ones:
Desktop Linux Distributions:
- Ubuntu,
- Linux Mint,
- Fedora,
- Debian, and
Server Linux Distributions:
- CentOS,
- Ubuntu Server,
- Debian,
- Red Hat Enterprise Linux (RHEL), and
24. How do you stay up-to-date with the latest developments in the Linux world?
Popular Linux distributions are available for desktops and servers in multiple varieties. Here are a few popular ones:
- Follow Linux News Websites,
- Subscribe to Mailing Lists,
- Follow Official Blogs & Social Media,
- Participate in Forums & Communities,
- Attend Linux Conferences & Events,
- Follow Developers & Influencers, and
- Experiment & Test.
Conclusion
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