stdin, stdout, and stderr

In computing, standard streams are preconnected input and output communication channels between a computer program and its environment. Specifically, stdin (standard input) is the channel through which a program receives input, typically from the keyboard or another program. stdout (standard output) is the channel through which a program writes its normal output, usually displayed on the screen. stderr (standard error) is the channel through which a program writes error messages and diagnostic information, also typically displayed on the screen, but kept separate from stdout to allow for easier handling of errors.

Visit the following resources to learn more:

• @article@Standard Streams - Wikipedia
• @article@stdin, stdout, stderr
• @video@Linux Crash Course - Data Streams (stdin, stdout & stderr)