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Systems & Data Center · Foundational

Standard Streams

The three default data channels of a Linux process: standard input (0), standard output (1) and standard error (2).

Definition

stdin usually reads from the keyboard and stdout and stderr write to the terminal. File descriptors 0, 1 and 2 can be redirected to files or connected to other commands via pipes.

Example

command > out.log 2> err.log separates normal output and errors.

Exam tip

Remember the numbers: 0 stdin, 1 stdout, 2 stderr.

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