pip install issue

• error

An error accour while using pip install (but python3 -m pip install is ok).

Traceback (most recent call last): 
File "/usr/bin/pip3", line 9, in from pip import main

ImportError: cannot import name 'main'

• reason

You must have inadvertently upgraded your system pip (probably through something like sudo pip install pip --upgrade)

pip 10.x adjusts where its internals are situated. The pip3 command you're seeing is one provided by your package maintainer (presumably debian based here?) and is not a file managed by pip.

You can read more about this onpip's issue tracker

You'll probably want tonotupgrade your system pip and instead use a virtualenv.

• fix

To recover the pip3 binary you'll need to sudo python3 -m pip uninstall pip && sudo apt install python3-pip --reinstall.

• reference
  python-pip3-cannot-import-name-main-error-after-upgrading-pip