python_shebang Description

This package provides a command that can be run from /usr/bin/env on the shebang line of a script that will find an appropriate python interpreter to run it.

Unlike plain /usr/bin/env this script allows specifying the version of python and python modules that are required.

Supported Operating Systems

This script is designed to operate on Unix operating systems. It is of no value on Windows which does not use shebang.

Dependencies

python_shebang is written to be able to run under any python version 2.6 or higher using only modules in the python standard library.

Examples

Here is a shebang line that will run the script with a python2.6 interpreter that has both the foo and bar modules:

#!/usr/bin/env python_shebang version:2.6 module:foo module:bar

This shebang line will run the script with a python 3 interpreter that has the paramiko module:

#!/usr/bin/env python_shebang version:3 module:paramiko

Running the command directly will give a python shell that meets the requirements (the asyncio module was added in python 3.4):

$ python_shebang module:asyncio
Python 3.4.0 (v3.4.0:04f714765c13, Mar 15 2014, 23:02:41)
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>>

If a compatible interpreter cannot be found it will generate an exception (the asyncio module was added in python 3.4)

$ python_shebang module:asyncio version:3.3
Traceback (most recent call last):
  File "/usr/bin/python_shebang", line 173, in <module>
    version, modules, python_interpreters=python_interpreters
  File "/usr/bin/python_shebang", line 139, in __search_for_interpreters
    raise PythonNotFound('No usable python interpreters found')
__main__.PythonNotFound: No usable python interpreters found