Linux Interview Questions & Answers

 Linux Interview Questions & Answers: 

 

1. What is the difference between hard links and soft links? 

Answer: Hard links point directly to the inode of a file, while soft links (or symbolic links) are separate files that contain the path to the target file. 

 

2. Explain the significance of the 'root' user in Linux. 

Answer: The 'root' user is the superuser with administrative privileges. It has the highest level of access and can perform any operation on the system. 

 

3. How do you find all files modified in the last 10 minutes in a directory and its subdirectories? 

Answer: Use the find command: find /path/to/directory -mmin -10. 

 

4. What is a kernel in Linux? 

Answer: The kernel is the core of the operating system that manages hardware resources and provides essential services for other parts of the system. 

 

5. Explain the purpose of the 'chmod' command. 

Answer: 'chmod' changes the permissions of a file or directory. It can add or remove read, write, and execute permissions for the owner, group, and others. 

 

6. How can you find out the current runlevel of a Linux system? 

Answer: Use the runlevel command: runlevel. 

 

7. Explain the role of the 'grep' command in Linux. 

Answer: 'grep' is used for searching text patterns in files. It can search for patterns using regular expressions and display matching lines. 

 

8. What is the purpose of the 'df' command? 

Answer: 'df' displays information about disk space usage on the filesystem. 

 

9. Explain the 'ps' command and how it is used to view processes. 

Answer: 'ps' shows information about currently running processes. Common options include ps aux to display detailed information about all processes. 

 

10. How do you change the priority of a process in Linux? 

Answer: Use the nice command to run a process with a specified priority. For example, nice -n 10 command sets a lower priority. 

 

11. What is the purpose of the 'awk' command? 

Answer: 'awk' is a versatile text processing tool that performs pattern scanning and text extraction. It is often used for data manipulation and reporting. 

 

12. Explain the role of the 'tar' command in Linux. 

Answer: 'tar' is used for creating and extracting archive files. It bundles multiple files into a single archive file and can compress the archive using various algorithms. 

 

13. How can you check the connectivity between two hosts using the 'ping' command? 

Answer: Use the ping command followed by the target IP or hostname: ping <target>. 

 

14. What is a cron job, and how do you create one? 

Answer: A cron job is a scheduled task in Linux. To create one, use the crontab -e command and add an entry specifying the schedule and the command to be executed. 

 

15. Explain the purpose of the 'iptables' command. 

Answer: 'iptables' is used for configuring the Linux kernel's netfilter firewall. It can filter, modify, or redirect network packets.