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Mastering Linux commands is crucial for efficiency in IT, DevOps, and cybersecurity. Below are 21 must-know Linux commands to boost your productivity and ace technical interviews.
File & Directory Operations
1. `ls` – List directory contents
ls -la Show hidden files with details
2. `cd` – Change directory
cd /var/www Navigate to a specific path
3. `pwd` – Print working directory
pwd Show current directory path
4. `mkdir` – Create a directory
mkdir new_folder Make a new directory
5. `rm` – Remove files/directories
rm -rf old_folder Force delete a folder
File Manipulation
6. `cp` – Copy files
cp file.txt /backup/ Copy file to another location
7. `mv` – Move/rename files
mv old.txt new.txt Rename a file
8. `cat` – Display file content
cat /etc/passwd View user accounts
9. `grep` – Search text in files
grep "error" /var/log/syslog Find errors in logs
10. `chmod` – Change file permissions
chmod 755 script.sh Make it executable
System Monitoring & Processes
11. `top` / `htop` – Monitor system processes
top Live system activity
12. `ps` – List running processes
ps aux | grep nginx Find specific process
13. `kill` – Terminate a process
kill -9 1234 Force kill process by PID
Networking Commands
14. `ifconfig` / `ip a` – Network interface info
ip a Show IP addresses
15. `ping` – Check network connectivity
ping google.com
16. `netstat` – Network statistics
netstat -tuln List open ports
Package Management
17. `apt` (Debian/Ubuntu)
sudo apt update && sudo apt upgrade
18. `yum` (RHEL/CentOS)
sudo yum install httpd
Compression & Archives
19. `tar` – Archive files
tar -czvf backup.tar.gz /home/
20. `gzip` / `gunzip` – Compress files
gzip large.log
User Management
21. `useradd` – Create a new user
sudo useradd -m newuser
You Should Know: Advanced Linux Command Tips
- Search for files quickly:
find / -name "*.conf" 2>/dev/null
- Check disk usage:
df -h Human-readable disk space
- Schedule tasks with
cron:crontab -e Edit cron jobs
- SSH into a remote server:
ssh [email protected]
What Undercode Say
Linux commands form the backbone of system administration, cybersecurity, and DevOps. Mastering these commands improves efficiency and troubleshooting skills. Practice them in a virtual lab or cloud server for hands-on experience.
Expected Output:
A well-structured cheat sheet of 21 essential Linux commands with practical examples for IT professionals.
Downloadable PDF Reference: Linux Commands Cheat Sheet (if available)
References:
Reported By: Namanjainai Linux – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
