Skip to content

Home

shtab

Downloads Tests Coverage PyPI conda-forge

  • What: Automatically generate shell tab completion scripts for Python CLI apps
  • Why: Speed & correctness. Alternatives like argcomplete and pyzshcomplete are slow and have side-effects
  • How: shtab processes an argparse.ArgumentParser object to generate a tab completion script for your shell

Features#

  • Outputs tab completion scripts for
    • bash
    • zsh
    • tcsh
  • Supports
  • Supports arguments, options and subparsers
  • Supports choices (e.g. --say={hello,goodbye})
  • Supports file and directory path completion
  • Supports custom path completion (e.g. --file={*.txt})

Installation#

pip install shtab

conda install -c conda-forge shtab

bash users who have never used any kind of tab completion before should also follow the OS-specific instructions below.

Recent versions should have completion already enabled. For older versions, first run sudo apt install --reinstall bash-completion, then make sure these lines appear in ~/.bashrc:

# enable bash completion in interactive shells
if ! shopt -oq posix; then
  if [ -f /usr/share/bash-completion/bash_completion ]; then
    . /usr/share/bash-completion/bash_completion
  elif [ -f /etc/bash_completion ]; then
    . /etc/bash_completion
  fi
fi

First run brew install bash-completion, then add the following to ~/.bash_profile:

if [ -f $(brew --prefix)/etc/bash_completion ]; then
  . $(brew --prefix)/etc/bash_completion
fi

FAQs#

Not working?

  • Make sure that shtab and the application you're trying to complete are both accessible from your environment.
  • Make sure that prog is set:
    • if using options.entry_points.console_scripts=MY_PROG=..., then ensure the main parser's prog matches argparse.ArgumentParser(prog="MY_PROG") or override it using shtab MY_PROG.get_main_parser --prog=MY_PROG.
    • if executing a script file ./MY_PROG.py (with a shebang #!/usr/bin/env python) directly, then use argparse.ArgumentParser(prog="MY_PROG.py") or override it using shtab MY_PROG.get_main_parser --prog=MY_PROG.py.
  • Make sure that all arguments have help messages (parser.add_argument('positional', help="documented; i.e. not hidden")).
  • Ask a general question on StackOverflow.
  • Report bugs and open feature requests on GitHub.

"Eager" installation (completions are re-generated upon login/terminal start) is recommended. Naturally, shtab and the CLI application to complete should be accessible/importable from the login environment. If installing shtab in a different virtual environment, you'd have to add a line somewhere appropriate (e.g. $CONDA_PREFIX/etc/conda/activate.d/env_vars.sh).

By default, shtab will silently do nothing if it cannot import the requested application. Use -u, --error-unimportable to noisily complain.

Alternatives#

  • argcomplete
    • executes the underlying script every time <TAB> is pressed (slow and has side-effects)
    • only provides bash completion
  • pyzshcomplete
    • executes the underlying script every time <TAB> is pressed (slow and has side-effects)
    • only provides zsh completion
  • click
    • different framework completely replacing the builtin argparse
    • solves multiple problems (rather than POSIX-style "do one thing well")

Contributions#

Please do open issues & pull requests! Some ideas:

  • support fish
  • support powershell

See CONTRIBUTING.md for more guidance.

Hits