Ubuntu/Unix Console Command -Cheat Sheet

Most popular Linux/Unix command those are required to know during working on Linux/Unix environment.

Primarily, when I started the work on ubuntu, I faced a common problem that was not familiar to know about the basic ubuntu command. After that, I aggregate basic commands and work very well.

Besides that, most of the time forgot the command and this helps me to cut-down googling time.

Privileges
SL	Command	Use / Description
1	sudo command	Run command as root
2	sudo -s	Open a root shell
3	sudo -s -u user	Open a shell as user
4	sudo -k	Forget sudo passwords
5	gksudo command	Visual sudo dialog (GNOME)
6	kdesudo command	visual sudo dialog (KDE)
7	sudo visudo	edit /etc/sudoers
8	gksudo nautilus	root file manager (GNOME)
9	kdesudo konqueror	root file manager (KDE)
10	passwd	change your password

 

File Commands
SL	Command	Use / Description
1	ls	Directory listing
2	ls -al	Formatted listing with hidden files
3	cd dir	Change directory to dir
4	cd	Change to home
5	pwd	show current directory
6	mkdir dir	create a directory dir
7	rm file	delete file
8	rm -r dir	delete directory dir
9	rm -f file	force remove file
10	rm -rf dir	force remove directory dir *
11	cp file1 file2	copy file1 to file2
12	cp -r dir1 dir2	copy dir1 to dir2; create dir2 if it doesn't exist
13	mv file1 file2	rename or move file1 to file2 if file2 is an existing directory, moves file1 into directory file2
14	ln -s file link	create symbolic link link to file
15	touch file	create or update file
16	cat > file	places standard input into file
17	more file	output the contents of file
18	head file	output the first 10 lines of file
19	tail file	output the last 10 lines of file
20	tail -f file	output the contents of file as it grows, starting with the last 10 lines Process Management

Process Management
SL	Command	Use / Description
1	ps	display your currently active processes
2	top	display all running processes
3	kill pid	kill process id PID
4	killall proc	kill all processes named proc *
5	bg	lists stopped or background jobs; resume a stopped job in the background
6	fg	brings the most recent job to the foreground
7	fg n	brings job n to the foreground

File Permissions
SL	Command	Use / Description
1	chmod octal file	– change the permissions of file to octal, which can be found separately for user, group, and world by adding: ● 4 – read (r) ● 2 – write (w) ● 1 – execute (x)
2	chmod 777	read, write, execute for all
3	chmod 755	rwx for owner, rx for group and world For more options

 

Firewall
SL	Command	Use / Description
1	ufw enable	turn on the firewall
2	ufw disable	turn off the firewall
3	ufw default allow	allow all connections bydefault
4	ufw default deny	drop all connections by default
5	ufw status	current status and rules
6	ufw allow port	allow traffic on port
7	ufw deny port	block port
8	ufw deny from ip	block ip adress

 

Installation
SL	Command	Use / Description
1	dpkg -i pkg.deb	install a package (Debian)
2	rpm -Uvh pkg.rpm	install a package (RPM)

 

Shortcuts
SL	Command	Use / Description
1	Ctrl+C	Halts the current command
2	Ctrl+Z	stops the current command, resume with fg in the foreground or bg in the background
3	Ctrl+D	log out of the current session, similar to exit
4	Ctrl+W	erases one word in the current line
5	Ctrl+U	erases the whole line
6	Ctrl+R	type to bring up a recent command
7	!!	repeats the last command
8	exit	log out of the current session

 

Package Management
SL	Command	Use / Description
1	apt-get update	refresh available updates
2	apt-get upgrade	upgrade all packages
3	apt-get dist-upgrade	upgrade with package replacements; upgrade Ubuntu version
4	apt-get install pkg	install pkg
5	apt-get purge pkg	uninstall pkg
6	apt-get autoremove	remove obsolete packages
7	apt-get -f install	try to fix broken packages
8	dpkg --configure -a	try to fix broken packages
9	dpkg -i pkg.deb	install file pkg.deb
10	(file) /etc/apt/sources.list	APT repository list

 

SSH
SL	Command	Use / Description
1	ssh user@host	connect to host as a user
2	ssh -p port user@host	connect to host on a port as user
3	ssh-copy-id user@host	add your key to host for the user to enable a keyed or passwordless login

System Info
SL	Command	Use / Description
1	date	show the current date and time
2	cal	show this month's calendar
3	uptime	show current uptime
4	w	display who is online
5	whoami	who you are logged in as
6	finger user	display information about the user
7	uname -a	show kernel information
8	cat /proc/cpuinfo	CPU information
9	cat /proc/meminfo	memory information
10	man command	show the manual for command
11	df	show disk usage
12	du	show directory space usage
13	free	show memory and swap usage
14	whereis app	show possible locations of app
15	which app	Show which app will be run by default

 

Compression
SL	Command	Use / Description
1	tar cf file.tar files	create a tar named file.tar containing files
2	tar xf file.tar	extract the files from file.tar
3	tar czf file.tar.gz files	create a tar with Gzip compression
4	tar xzf file.tar.gz	extract a tar using Gzip
5	tar cjf file.tar.bz2	create a tar with Bzip2 compression
6	tar xjf file.tar.bz2	extract a tar using Bzip2
7	gzip file	compresses file and renames it to file.gz
8	gzip -d file.gz	decompresses file.gz back to file

Network
SL	Command	Use / Description
1	ping host	ping host and output results
2	whois domain	get whois information for the domain
3	dig domain	get DNS information for the domain
4	dig -x host	reverse lookup host
5	wget file	download file
6	wget -c file	continue a stopped download
7	ifconfig	show network information
8	iwconfig	show wireless information
9	sudo iwlist scan	scan for wireless networks
10	sudo /etc/init.d/networking restart	resetnetwork for manual configurations
11	(file) /etc/network/interfaces	manual configuration
12	ifup interface	bring interface online
13	ifdown interface	disable interface

 

Searching
SL	Command	Use / Description
1	grep pattern files	Search for a pattern in files
2	grep -r pattern dir	Search recursively for a pattern in dir
3	command | grep pattern	Search for a pattern in the output of the command
4	locate file	find all instances of file

 

Helpful command
SL	Command	Use / Description
1	clear	Clear the screen
2	whoami	List who is logged in the session
3	echo string	Copies string to a terminal
4	date	List the current date and time
5	cal	Display a calendar
6	whereis command	Displays a command’s location in the directory structure
7	who	List currently logged in users
8	startx	Goes from command mode to graphical mode