Essential linux CLI commands

ssh	`ssh -p 8080 username@server`	ssh into a server
pwd		show current directory
touch	`touch file_name`	create a file
echo	`echo "some_text" > file_name`	add text into a file
nano	`nano file_name`	text editor
vim	`vim file_name`	text editor (i to edit / :wq to save&exit)
cat	`cat file_name`	show the content of a file
shred	`shred file_name`	obfuscate the content of a file
mkdir	`mkdir folder_name`	create a folder
cp	`cp file_name file_name_2`	copy a file
mv	`mv file_name destination_folder/` `mv file_name new_file_name`	move a file to a folder or rename a file
rm	`rm file_name` `rm -r folder_name/`	delete a file or a non-empty folder
rmdir	`rmdir folder_name/`	delete a folder
ln	`ln -s file_name name_of_the_link`	create a link / with -s a soft link
clear		cleanup console screen
whoami		display the current user name
adduser	`adduser user_name`	create a new user (same as the lowlevel command useradd)
deluser	`deluser user_name`	delete a user (same as the lowlevel command userdel)
sudo	`sudo command`	execute a command with admin right
su	`su user_name`	change into another user
exit		exit current program / sometimes need to use "q" or CTRL-C instead
apt	`apt update`	query the package manager
man	`man package_name`	query the help for a package
finger	`finger user_name`	inspect a user
whatis	`whatis package_name`	explain what the package is
whereis	`whereis file_name`	display all the location of the file_name / shows more than which
wget	`wget remote_file`	download a remote file / pros -> can download recursively to spider a website
curl	`curl remote_file > new_remote_file_name`	download a remote file whith added options
zip	`zip archive_name file_to_archive`	archive a file or a folder
unzip	`unzip archive_name`	deflate an archive
head	`head -n 20 file_name`	show only the 20 first lines of a file
tail	`tail -n 15 file_name`	show only the 15 last lines of a file
cmp	`cmp file_1 file_2`	compare files and tell if there is any difference
diff	`diff file_1 file_2`	compare files and show exactly what the differences are
sort	`cat file_name \| sort`	show the file_name sorted alphabetically
find	`find / -name "file_name"` `find . -type f -name ".*"` `find . -type f -empty` `find . -perm /a=x`	find a file_name anywhere `/` or in the same directory `.` find hidden files find empty directory find all executable files
chmod	`chmod +x file_name`	change the attribute of a file
chown	`chown user:usergroup file_name`	change the ownership of a file
grep	`ip address \| grep eth0"`	find a specific element when making a query
awk	`ip address \| awk '{print $2}'`	more powerfull and complex than grep, find a specific element when making a query

ifconfig		show the IP adress and details about the network
ip address		show the IP adress and details about the network
ping	`ping -c 5 ip_address` `ping domain_name`	ping a domain or an ip address to see if the other side is up
netstat	`netstat -tulpn`	check the ports on a machine
ss	`ss -tulpn`	check the ports of a machine / `-tulpn` to show only active servers
traceroute	`traceroute domain_name`	show the path to get to the website
iptables	`sudo iptables -I INPUT -p tcp -m tcp --dport 80 -j ACCEPT`	add rules to the built-in firewall
ufw	`sudo ufw status`	a simplified layer over iptables

uname	`uname -a`	show details about the machine
neofetch	`sudo apt install neofetch && neofetch`	show prettier details about the machine
cal		show a calendar
free		show the current memory allocation
df	`df -H`	show the space used/available on the machine
ps	`ps -aux`	show all the processes
top		show all the processes in a gui
htop		show all the processes in a prettier gui
kill	`ps -aux \| grep process_name` `kill -9 process_id`	kill a process with it's id
pkill	`pkill -f process_name`	kill a process with it's name
systemctl	`systemctl status`	start/stop/restart services
history		show the typed history of the user
reboot	`reboot` `reboot -f`	reboot the machine reboot forcibly
shutdown	`shutdown -h now` `shutdown -h +5 "message"` `shutdown -r +5` `shutdown -c`	shutdown the machine now shutrdown in 5 minutes with a message restart the machine in 5 minutes cancel the shutdown

¶ Essential linux CLI

¶ FILES

¶ NETWORK

¶ SYSTEM

¶ Examples

¶ grep command examples