linux

Cheat Sheet: UNIX Commands

1. Basic Commands

Command	Description	Example
ls	List directory contents	ls -l (detailed list)
cd	Change directory	cd /home
pwd	Print working directory	pwd
mkdir	Create a new directory	mkdir newdir
rmdir	Remove an empty directory	rmdir olddir
rm	Remove files or directories	rm file.txt
cp	Copy files or directories	cp src dest
mv	Move or rename files or directories	mv old new

2. Networking

Command	Description	Example
ifconfig	Configure network interface parameters	ifconfig eth0
ping	Check network connectivity	ping google.com
netstat	Networking statistics	netstat -r
traceroute	Trace route to a network host	traceroute google.com

3. File Permissions and Ownership

Command	Description	Example
chmod	Change file modes or Access Control Lists (ACL)	chmod 755 file.sh
chown	Change file owner and group	chown user:group file
umask	Set default file permissions	umask 022

4. Process Management

Command	Description	Example
ps	Report a snapshot of current processes	ps aux
top	Display Linux tasks	top
kill	Send a signal to a process	kill -9 1234
nohup	Run a command immune to hangups	nohup ./script.sh &

5. System Information and Performance

Command	Description	Example
uname	Print system information	uname -a
df	Report file system disk space usage	df -h
du	Estimate file space usage	du -sh /home/
free	Display memory usage	free -m

6. Archiving and Compression

Command	Description	Example
tar	Store and extract files from a tarfile	tar -xvf file.tar
gzip	Compress or expand files	gzip file
gunzip	Decompress files	gunzip file.gz

7. Text Processing

Command	Description	Example
grep	Search text for patterns	grep "hello" file
awk	Pattern scanning and processing language	awk '{print $1}' file
sed	Stream editor for filtering and transforming	sed 's/old/new/g' file

8. Scripting and Automation

Command	Description	Example
bash	Execute commands from a file or string	bash script.sh
crontab	Schedule periodic background jobs	crontab -e

9. User and Group Management

Command	Description	Example
useradd	Create a new user account	useradd newuser
usermod	Modify a user account	usermod -aG sudo newuser
userdel	Delete a user account	userdel olduser
groupadd	Create a new group	groupadd newgroup
groupdel	Delete a group	groupdel oldgroup
passwd	Change or set a user password	passwd username

10. Advanced File Manipulation

Command	Description	Example
find	Search for files in a directory hierarchy	find / -name "myfile.txt"
locate	Find files by name using indexed database	locate myfile.txt
touch	Change file timestamps or create empty files	touch newfile.txt
ln	Create hard and symbolic links	ln -s sourcefile link

11. System Services and Process Control

Command	Description	Example
systemctl	Control and manage systemd system and services	systemctl status nginx
service	Manage SysV services	service nginx start
ps	Report a snapshot of current processes	ps aux
kill	Send a signal to a process	kill -9 1234
top	Display and update sorted information about processes	top
htop	Interactive process viewer (enhanced top)	htop

12. Networking and Firewalls

Command	Description	Example
ip	Show / manipulate routing, devices, policy routing	ip addr show
iptables	Administration tool for IPv4 packet filtering and NAT	iptables -L
firewalld	Manage firewall with zones	firewall-cmd --list-all-zones
ss	Utility to investigate sockets	ss -tulwn

13. System Monitoring and Logs

Command	Description	Example
dmesg	Display message or driver message from kernel ring buffer	`dmesg
vmstat	Report virtual memory statistics	vmstat 1 5
iostat	Report CPU statistics and I/O statistics	iostat 1 5
netstat	Print network connections, routing tables, interface statistics	netstat -r
journalctl	Query contents of systemd journal	journalctl -u nginx.service

14. Archiving and Compression

Command	Description	Example
tar	Archive files	tar -cvf archive.tar /dir
gzip	Compress or expand files	gzip file
gunzip	Decompress files	gunzip file.gz
zip	Package and compress files	zip archive.zip file1 file2
unzip	Extract compressed files in a ZIP archive	unzip archive.zip

15. Text Processing

Command	Description	Example
grep	Search text for patterns	grep "pattern" file
awk	Pattern scanning and processing language	awk '/pattern/ {print $1}' file
sed	Stream editor for filtering and transforming text	sed 's/old/new/g' file
cut	Remove sections from each line of files	`cut -