LINUX
COMMANDS CHEATSHEET.

File & Directory Commands

Command	Description	Example
ls	List directory contents	ls -la
cd	Change directory	cd /home/user
pwd	Print working directory	pwd
mkdir	Create directory	mkdir -p dir/subdir
rmdir	Remove empty directory	rmdir dir
rm	Remove files/directories	rm -rf dir
cp	Copy files/directories	cp -r src dest
mv	Move/rename files	mv file1 file2
touch	Create empty file or update timestamp	touch file.txt
ln	Create links	ln -s target link
find	Search for files	find . -name "*.txt"
locate	Find files (updatedb database)	locate file.txt
which	Show location of command	which python
stat	File information	stat file.txt

Viewing Files

Command	Description	Example
cat	Display entire file	cat file.txt
less	View file interactively	less file.txt
more	View file page by page	more file.txt
head	First lines of file	head -n 20 file.txt
tail	Last lines of file	tail -f file.txt
wc	Word/line/char count	wc -l file.txt
diff	Compare files	diff file1 file2
file	Determine file type	file file.txt

Permissions

Command	Description	Example
chmod	Change permissions	chmod 755 file
chown	Change owner	chown user:group file
chgrp	Change group	chgrp users file
umask	Default file permissions	umask 022
lsattr	List file attributes	lsattr file
chattr	Change file attributes	chattr +i file

Permission Numeric Values

• 4 – read (r)
• 2 – write (w)
• 1 – execute (x)
• 7 – rwx (4+2+1)
• 6 – rw- (4+2)
• 5 – r-x (4+1)
• 4 – r-- (4)

Process Management

Command	Description	Example
ps	List processes	ps aux
top	Interactive process viewer	top
htop	Better interactive process viewer	htop
kill	Send signal to process	kill -9 PID
pkill	Kill process by name	pkill firefox
killall	Kill all processes by name	killall firefox
nice	Set process priority	nice -n 10 command
renice	Change process priority	renice 10 PID
jobs	List background jobs	jobs
bg	Resume background job	bg %1
fg	Resume foreground job	fg %1
nohup	Run command even after logout	nohup command &

Process Signals

• SIGTERM (15) – graceful termination
• SIGKILL (9) – force kill
• SIGHUP (1) – reload configuration
• SIGSTOP (19) – pause process
• SIGCONT (18) – resume paused process

Text Processing

Command	Description	Example
grep	Search for pattern	grep -r "pattern" .
sed	Stream editor	sed 's/old/new/g' file
awk	Text processing language	awk '{print $1}' file
cut	Cut columns/fields	cut -d',' -f1 file.csv
sort	Sort lines	sort -n file
uniq	Unique lines	sort file | uniq -c
wc	Word count	wc -l file
tr	Translate/delete characters	tr 'a-z' 'A-Z'
head	First lines	head -n 10 file
tail	Last lines	tail -n 10 file

grep Patterns

• grep pattern file – search file
• grep -i – case‑insensitive
• grep -v – invert match
• grep -r – recursive
• grep -E – extended regex
• grep -c – count matches
• grep -n – show line numbers
• grep -A 3 – show 3 lines after match

sed Examples

• sed 's/old/new/g' – replace all
• sed -n '5p' – print line 5
• sed '/pattern/d' – delete matching lines
• sed -i – in‑place edit
• sed '1,5d' – delete lines 1‑5

System Information

Command	Description	Example
uname	System information	uname -a
df	Disk usage	df -h
du	Directory size	du -sh dir
free	Memory usage	free -h
uptime	System uptime	uptime
who	Logged in users	who
w	Logged in users + activity	w
whoami	Current user	whoami
id	User/group info	id user
date	Current date/time	date
cal	Calendar	cal 2024

Networking

Command	Description	Example
ping	Test connectivity	ping google.com
curl	Transfer data from URL	curl http://example.com
wget	Download file	wget http://example.com/file
ifconfig	Network interfaces	ifconfig
ip	Advanced network config	ip addr
nslookup	DNS lookup	nslookup google.com
dig	DNS query tool	dig google.com
netstat	Network statistics	netstat -tuln
ss	Socket statistics	ss -tuln
traceroute	Trace route	traceroute google.com
telnet	Connect to port	telnet localhost 80
ssh	Secure shell	ssh user@host
scp	Secure copy	scp file user@host:/path
rsync	Remote sync	rsync -av src/ dest/

Archiving & Compression

Command	Description	Example
tar	Archive files	tar -czf archive.tar.gz dir/
gzip	Compress with gzip	gzip file
gunzip	Decompress gzip	gunzip file.gz
zip	Create zip archive	zip archive.zip file
unzip	Extract zip	unzip archive.zip
zcat	View gzipped file	zcat file.gz

tar Flags

• -c – create archive
• -x – extract archive
• -z – gzip compression
• -j – bzip2 compression
• -v – verbose
• -f – file
• -t – list contents

User Management

Command	Description	Example
useradd	Create user	useradd -m -s /bin/bash user
usermod	Modify user	usermod -aG sudo user
userdel	Delete user	userdel -r user
passwd	Change password	passwd user
groupadd	Create group	groupadd group
groupdel	Delete group	groupdel group
groups	Show user groups	groups user
su	Switch user	su - user
sudo	Execute as superuser	sudo command

Package Management

Debian/Ubuntu (apt)

• apt update – update package lists
• apt upgrade – upgrade packages
• apt install package – install package
• apt remove package – remove package
• apt purge package – remove with config
• apt search pattern – search packages
• apt show package – show package info
• apt list --installed – list installed packages

RedHat/CentOS/Fedora (yum/dnf)

• yum update / dnf update – update
• yum install package / dnf install package
• yum remove package / dnf remove package
• yum search pattern / dnf search pattern
• yum info package / dnf info package

Arch Linux (pacman)

• pacman -Syu – update
• pacman -S package – install
• pacman -R package – remove
• pacman -Qs pattern – search
• pacman -Qi package – info

Snap

• snap install package – install snap
• snap remove package – remove snap
• snap refresh – update snaps
• snap find pattern – search
• snap list – list installed snaps

Flatpak

• flatpak install flathub package – install
• flatpak remove package – remove
• flatpak update – update
• flatpak list – list installed
• flatpak search pattern – search

Miscellaneous Commands

Command	Description	Example
echo	Print to stdout	echo "Hello"
clear	Clear terminal	clear
history	Command history	history | grep command
alias	Create alias	alias ll='ls -la'
unalias	Remove alias	unalias ll
exit	Exit shell	exit
sleep	Delay execution	sleep 5
time	Measure execution time	time command
watch	Execute periodically	watch -n 2 command

Keyboard Shortcuts

• Ctrl + C – interrupt current process
• Ctrl + Z – suspend process
• Ctrl + D – EOF / exit shell
• Ctrl + L – clear terminal
• Ctrl + R – reverse history search
• Ctrl + A – move to beginning of line
• Ctrl + E – move to end of line
• Ctrl + U – delete from cursor to beginning
• Ctrl + K – delete from cursor to end
• Ctrl + W – delete previous word
• Ctrl + Shift + C – copy
• Ctrl + Shift + V – paste
• Tab – autocomplete
• ↑ / ↓ – command history