Things on this page are fragmentary and immature notes/thoughts of the author. Please read with your own judgement!
When installing a Python package using pip
without using sudo or the root user,
the package is installed into the user's local directory at
~/.local/lib/python3.7/site-packages (using Python 3.7 as example).
if sudo or the root user is used with pip,
then the package is installed to the system-wide location at
/usr/local/lib/python3.7/site-packages (using Python 3.7 as example).
One potentially very tricky thing that
the above statement applies to direct shell commands only.
Let's say that you run a Python program as a regular user dclong with out sudo,
and you use the subprocess module to revoke a shell command like below.
import subprocess as sp
sp.run("sudo pip3 install pandas", shell=True)
The Python package pandas will be installed to the local directory of the user dclong
even if sudo is used in this case!!
If you have used the root user to run the above Python script,
the Python package pandas will be installed to the local directory
(/root/.local/lib/python3.7/site-packages) of the root user.
Instead of invoking a sudo pip3 install ... in the Python script,
you can just invoking pip3 install ... in thee Python script
and run your Python script with sudo.
This fixes the tricky issue.
There are a few options to give users fine control on the destination directory to install Python packages.
--user
Install to the Python user install directory for your platform.
Typically ~/.local/,
or %APPDATA%Python on Windows.
(See the Python documentation for site.USER_BASE for full details.)
Generally speaking,
you do not have to specify this option manually
as Python packages are installed to the user's local directory by default
unless sudo or the root user is used.
The --user can be useful if you install a Python package using setup.py.
python setup.py install --user
--root
Install everything relative to this alternate root directory.
--prefix
Installation prefix where lib, bin and other top-level folders are placed
-t, --target
Install packages into