Linux commands – (Cheat Sheet)

You can do a lot using just commands on Linux. Through the Terminal, you can type the command that you want and perfume many actions and diagnostics. Depending on the distro you are using, you will have a different shell pre-installed (bash, dash, etc.). They can have small differences, but for the majority of command, they will work the same.
You can also change the shell if you like. Here you can see a Linux commands cheat sheet with the main commands and what they do. 

MTR command – Everything you need to know

SYSTEM		HARDWARE
uname	Information about the system	dmesg	Show bootup messages
uname -r	Information about the kernel release	cat /proc/cpuinfo	CPU information
hostname	System’s hostname	cat /proc/meminfo	Memory information
hostname –i	The IP of the system’s host	lshw	List the hardware components
last reboot	System reboot history	lsbkl	List block devices
date	Current system’s time and date	free –m	Shows free memory
timedatectl	Change system’s clock	lsspci –tv	Shows list of PCI devices
cal	Calendar, month and day	lsusb –tv	Shows list of USB devices
w	Shows which user is currently logged	dmidecode	Shows hardware information from the BIOS
whoami	User’s information	hdparm -i /dev/xda	Shows information about disk data
finger username	Show information for a particular user	hdparm -tt /dev/xda <:code>	Performs read speed test (disk)
USERS		badblocks -s /dev/xda	Checks for bad blocks on disk
id	Shows information about the current user	FILES
last	Shows last login	ls –al	List of all files including hidden
who	Shows who is logged in	pwd	Shows the current directory’s path
groupadd “admin”	Adds “admin” group	mkdir ‘new’	Makes new directory called “New”
adduser “michael”	Adds “Michael” as a user	rm file_name	Removes the file you wrote
userdel “michael”	Deletes “Michael” from users	rm -f filename	Removes the file you wrote with force
usermod	Changes user’s information	rm -r directory_name	Removes the directory you wrote recursively
PROCESS		rm -rf directory_name	Removes the directory you wrote recursively and forcefully
ps	Shows active processes	cp filea fileb	Copies the content of filea to fileb
ps aux | grep ‘telnet’	Seaches the “telnet” process’ id number	cp -r dira dirb	Copies dira to dirb recursively. Creates dirb if doesn’t exist
pmap	Shows processes’ memory map	mv filea fileb	Moves, renames filea to fileb
top	Shows all running processes	ln -s /path/to/file_name   link_name	Symbolic link to file_name
kil pid	Kills process with a given pid	touch file_name	Creates a new file (file_name)
killall proc	Kills all processes named proc	cat > file_name	Puts standard input into a file
pkill process-name	Sends a signal to a process with its name	more file_name	Outputs file’s content
bg	Resumes background processes	head file_name	Shows the first 10 lines of the file
fg	Foreground for the suspended jobs	tail file_name	Shows the last 10 lines of the file
fg name	Foreground for the job “name”	gpg -c file_name	Encrypts a file
lsoft	List of files that processes have opened	gpg file_name.gpg	Decrypts a file
renice 19 pid	Runs the pid with low priority “19”	wc	Prints bytes, words ,and line into a file
pgrep name	Find “name” process ID	xargs	Executes commands from standard input
pstree	Shows processes in a tree model	INSTALL SOURCE (COMPILATION)
INSTALL PACKAGES		./configure	Checks the system for the required software for building the program. Creates a Makefile container.
rpm -i pkg_name.rpm	Installs a rpm package	make	Reads the Makefile to compile the program.
NETWORK		make install	Installs the binaries after the compilation.
ip addr show	Shows IP addresses and all network interfaces	LOGIN
192.168.0.1/24 dev eth0	Assigns 192.168.0.1 (IP address) to eth0 (interface)	ssh user@host	Securely connect to host as user
ping  host	Ping a host and see the connection	ssh -p port_number user@host	Securely connect to host using a specified port
whois domain	Shows information about the domain	ssh host	Securely connect to the system via SSH default port 22
dig domain	DNS information about the domain	telnet host	Connect to host via telnet default port 23
host domain	DNS information about the domain	DISK USAGE
netstat -pnltu	Shows all active listening ports	df -h	Shows free space on the mounted system
DIRECTORY TRAVERSE		df -i	Shows free space inodes on file system
cd ..	Up one level in the directory	fdisk  -l	Shows disk partitions, sizes, and types
cd	Changes directory to the Home directory	du  -sh	Shows disk usage in the current directory
cd /test	Changes directory to  /test	findmnt	Displays target mount point for all filesystems
		mount device-path mount-poin	Mount a device

You can print this Linux commands cheat sheet and use it as much as you like in your job. It could save you time and make you more productive.