cd Change Directory.
mkdir Create a new folder (directory).
touch Create a new file.
rm Remove a file.
cat Show contents of a file.
pwd Show current directory (full path to where you are right now).
cp Copy file/folder.
mv Move file/folder.
grep Search for a specific phrase in file/lines.
find Search files and directories.
vi/nano Text editors.
history Show last 50 used commands.
clear Clear the terminal screen.
tar Create & Unpack compressed archives.
wget Download files from the internet.
du Get file size.