Help message
A help message is command-line documentation that explains a program’s invocation syntax, arguments, options, and usage.
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A help message is command-line documentation printed by a program to explain its invocation syntax and available arguments or options.
- How it is used
- Guides command-line users through program invocation, arguments, options, and input requirements.
- How deep it goes
- Explains generated usage output and argument errors through argparse, but does not descend into parser internals.
- Examples
- Demonstrates hello.py, scrambler.py, mad.py, gematria.py, picnic.py, gashlycrumb.py, and friar.py help output.
- What you can do after
- Apply it via argparse to create documented command-line programs with standard help output and validation feedback.
Go by Example
A usage message is command-line help text describing a program's available options, types, defaults, and invocation syntax.
- How it is used
- Guides command-line users through available options, defaults, required inputs, and valid invocation syntax.
- How deep it goes
- Explains handwritten and FlagSet-generated help, then customizes output for positional arguments; it does not cover broader CLI documentation.
- Examples
- Uses the HIT tool, multiline raw strings, generated `-h` output, invalid flag input, and a positional HTTP server URL.
- What you can do after
- Build it from scratch, generate help with Go's flag package, or customize usage for required positional arguments.
Related concepts
- help optionproduced by · A help option is a command-line option that displays a program’s usage information and available options.
- command-line interfaceused by · A command-line interface is a text-based interface through which users or programs interact with software or a computer by entering commands and receiving output.
- flag.FlagSetproduced by · flag.FlagSet is a Go flag package type that defines a set of command-line flags and manages their parsing and usage behavior.
- argparseproduced by · argparse is Python’s standard-library module for defining and parsing command-line arguments and generating related usage, help, and error information.
- command-line tooluses · A command-line tool is a software program operated through textual commands, options, or arguments in a command-line interface.
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