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Ecosystem · medium

36. Building CLIs

Commands, flags and exit codes.

1 min read2 questionsup to 50 XPtopic 36/50

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Small tools use the flag package; larger ones use cobra for subcommands, help text and completion. Return non-zero exit codes on failure, write errors to stderr, and keep output machine-friendly with a --json mode for scripting.

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  2. 2. Re-read the code snippets and say out loud what each line does.
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Check your understanding

  1. 1. Errors should be written to…

  2. 2. Which library adds subcommands?

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