Module’s Main

Python module can be invoked using python -m module.name. This will invoke:

• the __main__.py if invoking a package and __main__.py exists.
• the module itself, and set __name__ as __main__.

Most of python tooling are encouraged to invoked in this manner.

• python -m pytest ...
• python -m venv ...
• pyhthon -m unicorn ...

Entrypoint

Some python package can be installed and invoked from shell directly with interfering with python.

$ python -m pip install great-tool
$ great-tool perform task

To achieve this, a special directory should be defined In side pyproject.toml:

[project.scripts]
my-command = "my_package.module1:obj"
another-cmd = "my_package.module2:func"

And when pip install the package, these commands will be add to ~/.local/bin/ which is typically part of $PATH. Each file will have something looks like below:

#!/usr/bin/python3.12
# -*- coding: utf-8 -*-
import re
import sys
from my_package.module1 import obj
if __name__ == '__main__':
    sys.argv[0] = re.sub(r'(-script\.pyw|\.exe)?$', '', sys.argv[0])
    sys.exit(obj())

The script wrapper has a shebang #!/user/bin/python3.12 which reference the interpreter used to install the package.