Input and output streams

During our journey into Ubuntu Server so far, we’ve worked quite a bit within the terminal. We’ve been able to inspect the contents of files, insert text into files, and more. We’ve actually been working with streams the entire time without knowing it. In this section, we’re going to talk about this subject in more detail.

If you’ve studied computer science at all, then you probably already know that output refers to things that are printed out of the computer (for example, text being printed to the screen, or onto paper from a printer) and input refers to data that is being entered into a computer, whether that be on the command line, into a file, or similar.

Linux takes this concept a bit further. Streams in Linux refer to a special way to handle what’s going in or out, and beyond the input and output streams, we also have a third that refers to errors.

Output streams in Linux are referred to as Standard...