Just a random list of useful Linux commands I use often.

List files

ls [args]

list files in a directory ls

show ownership of files ls -l

Copy

cp [source] [dest]

copy file1 into file2 cp file1 file2

Move

mv [source] [dest]

move file from dir1 to dir2 mv dir1/file dir2/file

rename file1 into file2 mv file1 file2

Remove

rm [args]

delete file rm file

delete entire directory and its files rm -rf dir/

APT

apt [args]

update package repositories apt update

update packages apt upgrade

remove package apt remove package1

Firewall

UFW

ufw [args]

enable ufw ufw enable

disable ufw ufw disable

show status / rules ufw status (verbose)

add a rule ufw allow-/-deny port

add a rule only for TCP ufw allow-/-deny port/tcp

add a rule only for UDP ufw allow-/-deny port/udp

IPTABLES