1. Filesystem Management

pwd → Print current directory path

ls → List files/directories

cd → Change directory

mkdir → Create a directory

rmdir → Remove an empty directory

touch → Create an empty file

rm → Remove files/directories

cp → Copy files/directories

mv → Move/rename files/directories

2. File Viewing & Editing

cat → View file contents

nano → Edit file using Nano editor

vi → Edit file using Vi editor

echo → Print text or write to file

head → View the first lines of a file

tail → View the last lines of a file

sort → Sort file contents

uniq → Remove duplicate lines

wc → Count words, lines, characters

3. Search & Help

find → Search for files/directories

grep → Search for text inside files

man → View command manual

history → Show command history

4. Permissions & Ownership

chmod → Change file permissions

chown → Change file owner

passwd → Change password

whoami → Show current user

5. System Info & Resources

uname → Show OS information

df → Check disk usage

du → View directory size

free → Show RAM & swap usage

hostname → Show machine name

uptime → Show system uptime

clear → Clear terminal screen

6. Process Management

top → View running processes

ps → List processes

kill → Terminate a process

7. Networking & Remote Access

ping → Test network connection

curl → Fetch data from a URL

wget → Download files from the internet

ifconfig → Configure network (or ip addr in newer systems)

ssh → Connect to remote server

scp → Copy files between machines

8. Archiving & Compression

zip → Compress to ZIP

unzip → Extract ZIP

tar → Create/extract TAR archives

9. System Control

shutdown → Shut down the system

reboot → Restart the system

10. Command Customization

alias → Create command shortcuts

unalias → Remove command shortcuts