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So far text we've been working with has been output to standard output, which I keep reminding you is mapped to your Terminal. But you can redirect text elsewhere.
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It is easy to not notice the difference between standard output and standard error when you're in an interactive Terminal session – because both outputs are sent to the Terminal. But they are separate streams, with different meanings.
When executing commands you will want to manipulate standard output and standard error appropriately – especially for 3rd party programs.
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