What's the difference between "pip install" and "python -m pip install"?

Question

I have a local version of Python 3.4.1 and I can run python -m pip install, but I'm unable to find the pip binary to run pip install. What's the difference between these two?

Answer 1

2014

They do exactly the same thing. In fact, the docs for distributing Python modules were just updated to suggest using python -m pip instead of the pip executable, because it's easier to tell which version of python is going to be used to actually run pip that way.

---

Here's some more concrete "proof", beyond just trusting my word and the bug report I linked :)

If you take a look at the pip executable script, it's just doing this:

from pkg_resources import load_entry_point
<snip>
load_entry_point('pip==1.5.4', 'console_scripts', 'pip')()

It's calling load_entry_point, which returns a function, and then executing that function. The entry point it's using is called 'console_scripts'. If you look at the entry_points.txt file for pip (/usr/lib/python2.7/dist-packages/pip-1.5.4.egg-info/entry_points.txt on my Ubuntu machine), you'll see this:

[console_scripts]
pip = pip:main
pip2.7 = pip:main
pip2 = pip:main

So the entry point returned is the main function in the pip module.

When you run python -m pip, you're executing the __main__.py script inside the pip package. That looks like this:

import sys
from .runner import run

if __name__ == '__main__':
    exit = run()
    if exit:
        sys.exit(exit)

And the runner.run function looks like this:

def run():
    base = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
    ## FIXME: this is kind of crude; if we could create a fake pip
    ## module, then exec into it and update pip.__path__ properly, we
    ## wouldn't have to update sys.path:
    sys.path.insert(0, base)
    import pip
    return pip.main()

As you can see, it's just calling the pip.main function, too. So both commands end up calling the same main function in pip/__init__.py.

Answer 2

2021

This only happens if you create the venv with PyCharm. Please check if Scripts/pip-script.py located in your virtual environment

pip install and python -m pip install -- is not really the same. Or welcome back into the HELL of VERSIONING & DEPENDENCIES :-(

I was used to type pip(.exe) install <name> if I want install a package. But I run into trouble, if I try to install package Pillow. It breaks every time with an error message.

Today I retry python -m pip install copy&pasted from the manual and it works. Before I ignored it and type pip.... Because I thought it is the same.

I start to dive a little bit deeper into pip and I find this question/answer. After a while I found that pip.exe calls the script <virtual-environment/Scripts>pip-script.py.

I fighting with the installation of package Pillow.

#! .\venv\Scripts\python.exe
# EASY-INSTALL-ENTRY-SCRIPT: 'pip==19.0.3','console_scripts','pip3'
__requires__ = 'pip==19.0.3'
import re
import sys
from pkg_resources import load_entry_point

if __name__ == '__main__':
    sys.argv[0] = re.sub(r'(-script\.pyw?|\.exe)?$', '', sys.argv[0])
    sys.exit(
        load_entry_point('pip==19.0.3', 'console_scripts', 'pip3')()
    )

I was a little bit surprised that pip.exe still use the old version 19.0.3 of the package and not the new installed version 21.0.1.

I changed the two version strings by hand to 21.0.1. And now pip.exe was able to install Pillow proper.

From now I understand why pip still complains that I use an old version of pip.

I think the old v19 pip has problem to detect the supported platform and therefore sources instead of binaries are installed.