Test your knowledge: command-line streams and exit status

Review

1. Which statement about sys.argv is correct?

   Command-line arguments arrive as strings. The first element identifies the launch entry in a launch-specific way.
2. Where should a program normally write result data intended for a pipe or redirection?

   Normal output goes to standard output; diagnostics conventionally go to standard error.
3. Which stream is appropriate for reading multiple lines supplied through a pipe?

   sys.stdin is a text stream that can be iterated line by line.
4. What does returning 0 from main() conventionally signal when its value is passed through SystemExit?

   A zero exit status conventionally signals success; nonzero values indicate an unsuccessful outcome.
5. Which statement correctly describes sys.exit(3)?

   sys.exit() raises SystemExit, allowing normal finally-block cleanup to run before the interpreter exits.
6. When should an ordinary CLI prefer argparse rather than manual sys.argv indexing?

   sys.argv exposes raw tokens; argparse provides structured parsing, validation, defaults, and help.