argcomplete 0.1.5

Bash tab completion for argparse

Warning: under development. Some things are a bit messy.

argcomplete - Bash completion for argparse

Argcomplete provides easy and extensible automatic tab completion of arguments and options for your Python script.

It makes two assumptions:

• You’re using bash as your shell

• You’re using argparse to manage your command line options

Argcomplete is particularly useful if your program has lots of options or subparsers, and if you can suggest completions for your argument/option values (for example, if the user is browsing resources over the network).

Installation

pip install argcomplete

Synopsis

Python code (e.g. my-awesome-script.py):

import argcomplete, argparse
parser = argparse.ArgumentParser()
...
argcomplete.autocomplete(parser)
parser.parse()
...

Shellcode (to be put in e.g. .bashrc):

eval "$(register-python-argcomplete my-awesome-script.py)"

Specifying completers

You can specify custom completion functions for your options and arguments. Completers are called with the following keyword arguments:

• prefix: The prefix text of the last word before the cursor on the command line. All returned completions should begin with this prefix.

• action: The argparse.Action instance that this completer was called for.

• parser: The argparse.ArgumentParser instance that the action was taken by.

Completers should return their completions as a list of strings. An example completer for names of environment variables might look like this:

def EnvironCompleter(prefix, **kwargs):
    return (v for v in os.environ if v.startswith(prefix))

If you specify the choices keyword for an argparse option or argument (and don’t specify a completer), it will be used for completions.

A completer that is initialized a set of all possible choices of values for its action might look like this:

class ChoicesCompleter(object):
    def __init__(self, choices=[]):
        self.choices = choices

    def __call__(self, prefix, **kwargs):
    return (c for c in self.choices if c.startswith(prefix))

To specify a completer for an argument or option, set the completer attribute of its associated action. An easy way to do this at definition time is:

from argcomplete.completers import EnvironCompleter

parser = argparse.ArgumentParser()
parser.add_argument("--env-var1").completer = EnvironCompleter
parser.add_argument("--env-var2").completer = EnvironCompleter
argcomplete.autocomplete(parser)

The following two ways to specify a static set of choices are equivalent for completion purposes:

from argcomplete.completers import ChoicesCompleter

parser.add_argument("--protocol", choices=('http', 'https', 'ssh', 'rsync', 'wss'))
parser.add_argument("--proto").completer=ChoicesCompleter(('http', 'https', 'ssh', 'rsync', 'wss'))

Acknowledgments

Inspired and informed by the optcomplete module by Martin Blais.

Links

• Home page

• Docs

• On pypi