Linux Command Cheat Sheet

The following are useful Linux commands to master.

Navigating Directories

Command	Description	Example
`pwd`	Print working directory	`pwd`
`cd`	Change directory	`cd ~/Desktop` `cd /etc` `cd ..` `cd Castle/Cellar`
`ls`	List directory contents	`ls -al` `ls -l` `ls *.txt`

Command	Description	Example
`touch`	Create a file	`touch new.txt`
`mv`	Move or rename files and directories	`mv old_name.txt new_name.txt` `mv *.txt ~/backups`
`cp`	Copy files and directories	`cp /etc/passwd ~/passwd` `cp backups_* ~/old_backups`
`mkdir`	Make a directory	`mkdir test_files`
`rm`	Remove files or directories	`rm deleteme.txt` `rm .backup` `rm backups_` `rm student` `rm -rf dir_to_be_deleted`
`tar`	Create and extract archives	`tar -czvf my.tar.gz *.txt` `tar -xvf file.tar.bz2`
`file`	View information about a file	`file file.tar.bz2`
`chmod`	Change file permissions	`chmod u+x program.sh` `chmod -x program.sh` `chmod 560 program.sh`
`nano`	Edit text files in easy mode	`nano config.txt`
`vim`	Edit text files in hard mode	`vim config.txt`
`>`	Output content to a file	`echo "test" > test.txt` `ls backup* > backup_list.txt`
`>>`	Append content to a file	`echo "test" >> test.txt`

Command	Description	Example
`cat`	Print all file contents	`cat file.txt`
`head`	Print the first lines in a file	`head file.txt` `head -n 5 file.txt`
`tail`	Print the last lines in a file	`tail file.txt` `tail -n 4 file.txt`
`less`	Display a file in a navigable format	`less file.txt`
`more`	Display a file line by line or page by page	`more file.txt`

Command	Description	Example
`grep`	Find text inside files	`grep -i fail auth.log` `grep -ir error ~/` `grep -il cash `
`find`	Find directories and files	`find . -name "log"` `find . -iname cash` `find / -name "*.txt" -type f` `find / -name "logs" -type d`

Command	Description	Example
`sudo apt udpate`	Updates the list of available packages	`sudo apt update`
`sudo apt upgrade`	Updates currently installed packages	`sudo apt upgrade`
`sudo apt install [x]`	Installs new packages	`sudo apt install nmap`
`alias`	Create an alias	`alias la='ls -A'`
`ps`	View running processes	`ps -A`
`kill`	Stop a process	`kill 634185` `kill -s 9 6352671` `kill -s TERM 633227 633123 633115`
`pstree`	View running processes as a tree	`pstree`
`top`	View running processes in real-time	`top`
`systemctl`	Manage services	`sudo systemctl start apache2`
`logger`	Manually create a log entry	`logger Backup started`

Command	Description	Example
`whoami`	Prints current user	`whoami`
`sudo`	Superuser do: run a command as root	`sudo ls /root`
`su`	Switch users (default is root)	`sudo su`
`exit`	Exit the terminal or switched user	`exit`
`useradd`	Add a user	`sudo useradd chris`
`passwd`	Change a user's password	`sudo passwd chris`

Command	Description	Example
`git`	Manage git source repositories	`git clone https://github.com/jimmarq/cyfunfiles`
`wget`	Download files from the internet	`wget https://some_site/file.zip`
`curl`	Download content from the internet	`curl https://www.google.com`

Command	Description	Example
`ifconfig`	View and change network information (old)	`ifconfig eth0`
`ip`	View and change network information (new)	`ip a`
`nmap`	Scan ports	`nmap scanme.nmap.org`
`nping`	Ping for enhanced network testing	`nping scanme.nmap.org -p 9929`
`tcpdump`	Capture network packets	`tcpdump -i eth0 -w telnet.pcap`
`telnet`	Connect to remote computers (unencrypted)	`telnet telehack.com`
`dig`	Query domain name information	`dig yahoo.com`
`ping`	Verify connectivity	`ping 192.168.1.1`

Command	Description	Example
`man`	Show the manual for a command	`man ls`
`echo`	Print text to the terminal	`echo "hi"`