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Linux Commands Interview Questions

Command-line proficiency is arguably the most critical skill for any Linux professional. These questions test your knowledge of common utilities.

Core Questions​

1. How do you find a file by name?​

The find command is the most robust tool for this.

find / -name "filename.txt"

To find files modified in the last 7 days:

find /path -mtime -7

2. How do you check memory and disk usage?​

  • Memory: free -m or free -h
  • Disk Usage: df -h (filesystem level) and du -sh /path (directory level).

3. What is the difference between grep, awk, and sed?​

  • grep: Used for searching text patterns within files.
  • awk: A powerful text processing language used for column-based data extraction and reporting.
  • sed: A stream editor used for modifying text on the fly (e.g., find and replace).

Practical Examples​

Using grep and awk together: Find all processes owned by a specific user and print their PIDs:

ps aux | grep username | awk '[print $2]'

(Note: brackets used instead of literal braces for documentation compatibility)

Best Practices​

  • Always mention flags like -h (human-readable) as it shows practical experience.
  • When explaining tools like sed or awk, provide a simple example of how you've used them in a script.