Common Interview Questions About Linux for Aspiring System Administrators

For individuals seeking to become system administrators, acing an interview that includes questions on Linux is crucial. This article provides a comprehensive overview of common interview questions, categorized by topic, to help candidates prepare effectively. From basic Linux commands to advanced concepts, these questions are designed to test one's knowledge and practical skills.

Basic Linux Commands

What is the command to list files in a directory?
Answer: ls

How do you copy files in Linux?
Answer: cp [source] [destination]

What command is used to move files?
Answer: mv [source] [destination]

How do you remove a file?
Answer: rm [filename]

File Permissions

What are the different types of file permissions in Linux?
Answer: Read (r), Write (w), Execute (x).

How do you change file permissions?
Answer: chmod [permissions] [filename]

What is the command to change the owner of a file?
Answer: chown [owner] [filename]

System Administration

What is the purpose of /etc/passwd?
Answer: It stores user account information.

How do you check disk usage in Linux?
Answer: df -h for disk space and du -sh [directory] for directory size.

What command would you use to view running processes?
Answer: ps aux or top.

Networking

How can you check the IP address of your machine?
Answer: ip addr or ifconfig.

What command is used to test connectivity to another host?
Answer: ping [hostname or IP].

Package Management

What package manager do you use on Debian-based systems?
Answer: apt.

How do you install a package using yum?
Answer: yum install [package-name].

Shell Scripting

What is a shebang?
Answer: It’s the first line in a script that indicates the interpreter to be used, e.g., !/bin/bash.

How do you create a variable in a shell script?
Answer: variable_namevalue.

Troubleshooting

What steps would you take to troubleshoot a server that is not responding?
Answer: Check network connectivity, review logs, check resource usage (CPU, memory), and ensure services are running.

How would you find a specific string in a file?
Answer: grep string [filename].

Advanced Topics

What is the difference between a hard link and a soft link?
Answer: A hard link points directly to the inode of a file while a soft link or symbolic link points to the filename.

Can you explain the Linux boot process?
Answer: The boot process involves the BIOS/UEFI bootloader like GRUB, kernel loading, and the init system like systemd starting user space.

These questions can help assess a candidate's familiarity with Linux from basic commands to more advanced concepts. By mastering these areas, a candidate can improve their chances of excelling in a Linux-based system administration interview.