man – The man command (short for ‘manual’) provides documentation on other commands. Try typing

man mkdir

q to exit the manual page reader

mkdir – The mkdir command (short for ‘make directory’) makes a new directory (or in macOS parlance, folder) in the current directory that you are currently accessing. Try typing

ls – The ls command (short for ‘list directory’) lists the contents of the current directory. Try typing

cd – The cd command (short for ‘change directory’) changes the current directory. Its argument specifies the directory to move to. You can give a subdirectory of the current directory to change to that subdirectory, or ‘'..’’ to change to the immediately enclosing directory. Try typing

rm – The rm command (short for ‘remove file’) deletes a file. Its argument specifies the file or files to be deleted. Be careful with this one.