stdin, stdout, and stderr

What happens when you type this command?

$ echo "Hello"

The echo command accepts the string "Hello" as standard input, and echoes the string "Hello" back to the terminal as standard output.

Let's learn more about standard input, standard output, and standard error:

  1. standard input, abbreviated as stdin, is information inputted into the terminal through the keyboard or input device.

  2. standard output, abbreviated as stdout, is the information outputted after a process is run.

  3. standard error, abbreviated as stderr, is an error message outputted by a failed process.

Redirection reroutes standard input, standard output, and standard error to or from a different location.

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