Complete A to Z Linux Commands Cheatsheet & Directory

A Commands

Command	Purpose & Explanation	Example
alias	Creates custom shortcuts for long CLI commands.	alias ll='ls -lah'
apt / apt-get	Debian/Ubuntu package manager to install/update software.	sudo apt update && sudo apt install nginx
awk	Powerful pattern scanning and column processing language.	awk '{print $1}' access.log
arch	Displays computer hardware processor architecture.	arch (e.g. x86_64 / aarch64)

B Commands

Command	Purpose & Explanation	Example
bash	Bourne Again SHell command language interpreter.	bash script.sh
bg	Sends a paused background job to continue running.	bg %1
blkid	Locates block devices and UUID filesystems.	sudo blkid

C Commands

Command	Purpose & Explanation	Example
cat	Concatenates and displays file contents in output stream.	cat /etc/os-release
cd	Changes current working directory.	cd /var/www/html/
chmod	Changes file read/write/execute access permissions.	chmod 400 key.pem
chown	Changes file owner user and group ownership.	sudo chown -R www-data:www-data /var/www/
clear	Clears the terminal screen buffer.	clear
cp	Copies files or directories from source to destination.	cp -r /src /dest
crontab	Schedules automated recurring background cron jobs.	crontab -e
curl	Transfers data to/from servers supporting HTTP/HTTPS/FTP.	curl -I https://teluguittutorials.com
cut	Removes sections or columns from each line of files.	cut -d: -f1 /etc/passwd

D Commands

Command	Purpose & Explanation	Example
date	Displays or sets system date and time.	date "+%Y-%m-%d %H:%M:%S"
df	Displays disk filesystem space usage in human units.	df -h
diff	Compares two files line by line showing differences.	diff file1.txt file2.txt
dig	DNS lookup utility for checking domain A/CNAME/MX records.	dig teluguittutorials.com
du	Estimates file space usage of directories.	du -sh /var/log/*

E Commands

Command	Purpose & Explanation	Example
echo	Prints text string or environment variable to terminal.	echo $PATH
env	Displays all active environment variables.	env
export	Sets environment variable for current and child processes.	export PORT=8080

F Commands

Command	Purpose & Explanation	Example
find	Searches for files in directory tree based on conditions.	find /var/log -name "*.log"
free	Displays free and used system RAM memory.	free -h

G Commands

Command	Purpose & Explanation	Example
git	Distributed version control system CLI tool.	git status
grep	Searches text files for matching regular expression patterns.	grep -rnI "ERROR" /var/log/
gzip	Compresses files using Lempel-Ziv coding (LZ77).	gzip app.log

H Commands

Command	Purpose & Explanation	Example
head	Outputs the first 10 lines of a file stream.	head -n 20 /var/log/syslog
history	Displays list of previously executed terminal commands.	history | grep ssh
htop	Interactive colored process viewer and RAM/CPU monitor.	htop

I Commands

Command	Purpose & Explanation	Example
ip	Manipulates network interfaces, routing tables, and IP addresses.	ip a / ip route
iptables	Administration tool for IPv4 packet filtering and firewall rules.	sudo iptables -L

J Commands

Command	Purpose & Explanation	Example
journalctl	Queries systemd journal logging daemon.	sudo journalctl -u nginx -f

K Commands

Command	Purpose & Explanation	Example
kill	Sends termination signal (e.g. SIGKILL 9) to a specific PID.	kill -9 1234
pkill	Sends signals to processes based on matching name.	pkill -f node

L Commands

Command	Purpose & Explanation	Example
ls	Lists directory contents with file details.	ls -lah
lsblk	Lists block devices (hard drives, EBS volumes, partitions).	lsblk
lsof	Lists open files and network sockets opened by processes.	sudo lsof -i :8080

M Commands

Command	Purpose & Explanation	Example
mkdir	Creates new empty directories.	mkdir -p /var/www/app
mount	Mounts a storage disk filesystem to a directory path.	sudo mount /dev/sdb1 /mnt/data
mv	Moves or renames files and directories.	mv old.txt new.txt

N Commands

Command	Purpose & Explanation	Example
nc (netcat)	Reads and writes data across network connections.	nc -zv db.internal 5432
netstat	Prints network connections, routing tables, and interface stats.	netstat -tulpn
nslookup	Queries Internet name servers interactively for IP hostnames.	nslookup google.com

P Commands

Command	Purpose & Explanation	Example
ping	Sends ICMP ECHO_REQUEST packets to network hosts.	ping 8.8.8.8
ps	Reports a snapshot of current active processes.	ps aux | grep python
pwd	Prints absolute path of current working directory.	pwd

R Commands

Command	Purpose & Explanation	Example
rm	Removes files or directories recursively.	rm -rf /tmp/cache
rsync	Fast, incremental file transfer tool over SSH.	rsync -avz ./dist/ user@server:/var/www/

S Commands

Command	Purpose & Explanation	Example
sed	Stream editor for filtering and transforming text inline.	sed -i 's/foo/bar/g' config.env
sort	Sorts lines of text files alphabetically or numerically.	sort -nr numbers.txt
ss	Modern utility to dump socket statistics (replaces netstat).	ss -tulpn
ssh	OpenSSH SSH client for secure remote terminal login.	ssh -i key.pem ubuntu@ec2-ip
sudo	Executes a command with root/super-user privileges.	sudo systemctl restart nginx
systemctl	Control tool for systemd system and service manager.	sudo systemctl status docker

T Commands

Command	Purpose & Explanation	Example
tail	Outputs the last part of files or streams live logs.	tail -f /var/log/syslog
tar	Archives multiple files into a single `.tar.gz` bundle.	tar -czvf app.tar.gz /app/
top	Displays Linux processes in real time.	top
touch	Creates empty files or updates file timestamps.	touch index.js

U Commands

Command	Purpose & Explanation	Example
ufw	Uncomplicated Firewall management tool for Ubuntu.	sudo ufw allow 80/tcp
uname	Prints system hardware and Linux kernel specifications.	uname -a
uniq	Filters out repeated identical adjacent lines.	uniq -c access.log
uptime	Shows how long the server has been running.	uptime

V, W, X, Z Commands

Command	Purpose & Explanation	Example
vim / vi	Modal terminal text editor.	vim /etc/nginx/nginx.conf
watch	Executes a command periodically, displaying output fullscreen.	watch -n 2 'free -m'
wc	Counts lines, words, and byte counts in files.	wc -l access.log
wget	Non-interactive network downloader.	wget https://example.com/file.zip
whoami	Prints current effective logged-in username.	whoami
xargs	Builds and executes commands from standard input streams.	find . -name "*.tmp" | xargs rm
zip / unzip	Packages and extracts compressed zip archives.	unzip build.zip -d /var/www/