2nd August 2026
🐧 Top 20 Linux Commands
Practical Syntax, Examples & Expected Output
1. pwd – Print Working Directory
Purpose: Displays the full path of your current directory.
Syntax
pwdExample
pwdOutput
/home/ram
Use Case
Verify your current location before creating, deleting, or moving files.
2. ls – List Files and Directories
Purpose: Shows the contents of a directory.
Syntax
ls [options]Common Options
| Option | Description |
|---|---|
| -l | Long listing format |
| -a | Show hidden files |
| -h | Human-readable file sizes |
| -t | Sort by modification time |
Example
ls -lahOutput
drwxr-xr-x Documents
-rw-r--r-- notes.txt
-rwxr-xr-x script.sh
-rw-r--r-- notes.txt
-rwxr-xr-x script.sh
3. cd – Change Directory
Purpose: Move from one directory to another.
| Action | Command |
|---|---|
| Go to Home | cd |
| Specific Directory | cd /var/log |
| One Level Up | cd .. |
| Previous Directory | cd - |
4. mkdir – Create Directory
Purpose: Creates new directories.
mkdir project
mkdir -p project/src/imagesResult
project/
└── src/
└── images/5. rm – Remove Files
rm file.txt
rm -r project
rm -rf project
⚠ Warning:
rm -rf permanently deletes files and directories.
6. cp – Copy Files
mv report.pdf backup.pdf
cp -r website backup/7. mv – Move or Rename Files
mv old.txt new.txt
mv report.pdf /home/ram/Documents/8. cat – Display File Contents
cat notes.txt
cat > hello.txt
Hello Linux
Ctrl + D9. grep – Search Text
grep "error" logfile.log
grep -i "warning" logfile.log
grep -r "password" /etc10. find – Find Files
find /home -name "*.pdf"
find . -empty
find . -mtime -711. chmod – Change Permissions
chmod +x install.sh
chmod 755 script.sh| Permission | Meaning |
|---|---|
| 7 | rwx |
| 5 | r-x |
| 4 | r-- |
12. chown – Change Ownership
sudo chown ram file.txt
sudo chown ram:developers project/
sudo chown -R apache:apache /var/www/html13. df – Disk Space
df -h
Filesystem Size Used Avail Use%
/dev/sda1 100G 62G 38G 62%
/dev/sda1 100G 62G 38G 62%
14. du – Directory Size
du -sh Downloads
du -sh * | sort -h15. ps – Running Processes
ps -ef
ps -ef | grep httpd
root 1523 httpd
apache 1534 httpd
apache 1534 httpd
16. top – Process Monitor
topShows
- CPU Usage
- RAM Usage
- Running Processes
- Load Average
- Uptime
Useful Keys
| Key | Action |
|---|---|
| P | Sort by CPU |
| M | Sort by Memory |
| k | Kill Process |
| q | Quit |
17. kill – Stop Process
kill 2345
kill -9 2345
pkill firefox18. systemctl – Manage Services
sudo systemctl start nginx
sudo systemctl stop nginx
sudo systemctl restart nginx
systemctl status nginx
sudo systemctl enable nginx19. tar – Archive Files
tar -cvf backup.tar project/
tar -czvf backup.tar.gz project/
tar -xzvf backup.tar.gz20. ssh – Remote Login
ssh user@192.168.1.20
ssh -p 2222 user@example.com
ssh -i ~/.ssh/id_rsa user@example.com