The command line

The command line is where you type a command and the system runs it. One line, one action. In this lesson you take apart what a command is made of and run a few simple ones: print words, look at a file, ask for the date, and chain commands together.

Every step saves its result to a file, and the check button looks at what came out. Nothing is scary to break: the sandbox is throwaway.

What to understand

A command is the name of a program followed by options and arguments. The name comes first: ls, echo, date.

An option is a switch that changes how the command behaves. An option usually has a short name with a dash: -l, -a. Options are optional.

An arg