docopt creates beautiful command-line interfaces


New in version 0.3.0: (sub)commands support, [options] shortcut.


Incompatible change in 0.3.0: docopt function returns a dict.

Isn’t it awesome how optparse and argparse generate help and usage-messages based on your code?!

Hell no! You know what’s awesome? It’s when the option parser is generated based on the beautiful usage-message that you write in a docstring! This way you don’t need to write this stupid repeatable parser-code, and instead can write only the usage-message—the way you want it.

docopt helps you create most beautiful command-line interfaces easily:

"""Naval Fate.

Usage: ship new <name>... ship [<name>] move <x> <y> [--speed=<kn>] ship shoot <x> <y> mine (set|remove) <x> <y> [--moored|--drifting] -h | --help --version

  -h --help     Show this screen.
  --version     Show version.
  --speed=<kn>  Speed in knots [default: 10].
  --moored      Mored (anchored) mine.
  --drifting    Drifting mine.

from docopt import docopt

if __name__ == '__main__':
    arguments = docopt(__doc__, version='Naval Fate 2.0')

Beat that! The option parser is generated based on docstring above, that you pass to docopt function. docopt parses the usage-pattern ("Usage: ...") and option-descriptions (lines starting with dash -) and ensures that program invocation matches the ussage-pattern; it parses options, arguments and commands based on that. The basic idea is that a good usage-message has all necessary information in it to make a parser.

Even pep257 recommends putting usage-message in the module docstrings.


Use pip or easy_install:

pip install docopt

Alternatively you can just drop file into your project—it is self-contained. Get source on github.

docopt is tested with Python 2.5, 2.6, 2.7, 3.1, 3.2.


from docopt import docopt
docopt(doc[, argv=sys.argv[1:]][, help=True][, version=None])

docopt takes 1 required and 3 optional arguments:

  • doc should be a module docstring (__doc__) or some other string that describes usage-message in a human-readable format, that will be parsed to create the option parser. The simple rules of how to write such a docstring are given in next sections. Here is a quick example of such a string:

    """Usage: [-hso FILE] [--quiet | --verbose] [INPUT ...]
    -h --help    show this
    -s --sorted  sorted output
    -o FILE      specify output file [default: ./test.txt]
    --quiet      print less text
    --verbose    print more text
  • argv is optional argument vector; by default it is the argument vector passed to your program (sys.argv[1:]). You can supply it with list of strings (similar to sys.argv) e.g. ['--verbose', '-o', 'hai.txt'].

  • help, by default True, specifies whether the parser should automatically print the usage-message (supplied as doc) and terminate, in case -h or --help options are encountered. If you want to handle -h or --help options manually (as all other options), set help=False.

  • version, by default None, is an optional argument that specifies the version of your program. If supplied, then, if parser encounters --version option, it will print the supplied version and terminate. version could be any printable object, but most likely a string, e.g. "2.1.0rc1".


when docopt is set to automatically handle -h, --help and --version options, you still need to mention them in doc. Also for your users to know about them.

The return value is just dictionary with options, arguments and commands, with keys spelled exactly like in usage-message (long versions of options are given priority). For example, if you invoke the top example as: ship Guardian move 100 150 --speed=15

the return dictionary will be:

{'--drifting': False,    'mine': False,
 '--help': False,        'move': True,
 '--moored': False,      'new': False,
 '--speed': '15',        'remove': False,
 '--version': False,     'set': False,
 '<name>': ['Guardian'], 'ship': True,
 '<x>': '100',           'shoot': False,
 '<y>': '150'}

This turns out to be the most straight-forward, unambiguous and readable format possible. You can instantly see that args['<name>'] is an argument, args['--speed'] is an options, and args['move'] is a command.

Usage-message format

Usage-message consists of 2 parts:

  • Usage-pattern, e.g.:

    Usage: [-hso FILE] [--quiet | --verbose] [INPUT ...]
  • Option-description, e.g.:

    -h --help    show this
    -s --sorted  sorted output
    -o FILE      specify output file [default: ./test.txt]
    --quiet      print less text
    --verbose    print more text

Their format is described below; other text is ignored. Also, take a look at our beautiful examples.

Usage-pattern format

Usage-pattern is a substring of doc that starts with usage: (case-insensitive) and ends with visibly empty line. Minimum example:



The first word after usage: is interpreted as your program’s name. You can specify your program’s name several times to signify several exclusive patterns:

"""Usage: FILE


Each pattern can consist of following elements:

  • <arguments>, ARGUMENTS. Arguments are specified as either upper-case words, e.g. CONTENT-PATH or words surrounded by angular brackets: <content-path>.
  • –options. Options are words started with dash (-), e.g. --output, -o. You can “stack” several of one-letter options, e.g. -oiv which will be same as -o -i -v. Options can have arguments, e.g. --input=FILE or -i FILE or even -iFILE. However it is important that you specify all option-descriptions (see next section).
  • commands are words that do not follow the described above conventions of --options or <arguments> or ARGUMENTS.

Use the following operators to specify patterns:

  • [ ] (brackets) optional elements. e.g.: [-hvqo FILE]
  • ( ) (parens) required elements. All elements that are not put in [ ] are also required, e.g.: --path=<path> <file>... is same as (--path=<path> <file>...). (Note, “required options” might be not a good idea for your users).
  • | (pipe) mutualy exclussive elements. Group them using ( ) if one of the mutually exclussive elements is required: (--clockwise | --counter-clockwise) TIME. Group them using [ ] if none of the mutually-exclusive elements are required: [--left | --right].
  • ... (ellipsis) one or more elements. To specify that arbitrary number of repeating elements could be accepted use ellipsis (...), e.g. FILE ... means one or more FILE-s are accepted. If you want to accept zero or more elements, use brackets, e.g.: [FILE ...]. Ellipsis works as unary operator on expression to the left.
  • [options] (case sensitive) shortcut for any options. You can use it if you want to specify that usage pattern could be provided with any options defined below in option-descriptions and do not want to enumerate them all in pattern.

If your usage-patterns allow to match same-named argument several times, parser will put matched values into a list, e.g. in case pattern is FILE FILE then args['FILE'] will be a list; in case pattern is FILE... it will also be a list.

Options-description format

Options-description is a list of options that you put below your ussage-patterns. It is required to list all options that are in ussage-patterns, their short/long versions (if any), and default values (if any).

  • Every line in doc that starts with - or -- (not counting spaces) is treated as an option description, e.g.:

      --verbose   # GOOD
      -o FILE     # GOOD
    Other: --bad  # BAD, line does not start with dash "-"
  • To specify that option has an argument, put a word describing that argument after space (or equals = sign) as shown below. You can use comma if you want to separate options. In the example below both lines are valid, however you are recommended to stick to a single style.

    -o FILE --output=FILE       # without comma, with "=" sign
    -i <file>, --input <file>   # with comma, wihtout "=" sing
  • Use two spaces to separate options with their informal description.

    --verbose More text.   # BAD, will be treated as if verbose option had
                           # an argument "More", so use 2 spaces instead
    -q        Quit.        # GOOD
    -o FILE   Output file. # GOOD
    --stdout  Use stdout.  # GOOD, 2 spaces
  • If you want to set a default value for an option with an argument, put it into the option description, in form [default: <my-default-value>].

    --coefficient=K  The K coefficient [default: 2.95]
    --output=FILE    Output file [default: test.txt]
    --directory=DIR  Some directory [default: ./]


docopt lives on github.

We would love to hear what you think about docopt on our issues page.

Contribute, make pull requrests, report bugs, suggest ideas and discuss docopt. You can also drop a line directly to

Porting docopt to other languages

We think docopt is so good, we want to share it beyound the Python community!

Help developing Ruby port, or create port for your favorite language! You are encouraged to use Python version as reference implementation. Language-agnostic test-suite is on it’s way to be developed.

Porting discussion is on issues page.


docopt follows semantic versioning. First release with stable API will be 1.0 (soon). Until then you are encouraged to specify explicitly the version in your dependency tools, e.g.:

pip install docopt==0.3.0
  • 0.3.0 Support for (sub)commands like git remote add. Introduce [options] shortcut for any options. Incompatible changes: docopt returns dictionary.
  • 0.2.0 Usage-pattern matching. Positional arguments parsing based on usage patterns. Incompatible changes: docopt returns namespace (for arguments), not list. Usage-pattern is formalized.
  • 0.1.0 Initial release. Options-parsing only (based on options-description).