Common Linux Shell/SSH Commands

apt (also apt-get, or aptitude)A command that allows you to install programs, libraries, and such, called “packages” in Linux.
suA command that allows you to switch to another user (switch user).
sudoA command that allows you to run another command with administrator privileges.
shell (also console or terminal)A shell is an interface that allows you to interact with a Linux system. On most graphical systems, you would use a mouse and keyboard to interact with the system, but in a shell, everything is text. In a shell, you use commands you type to interact with and control the system.
SSHStands for secure shell. (See shell.)