$ sudo pip uninstall virtualenv
WARNING: Skipping virtualenv as it is not installed.
$ sudo pip3 uninstall virtualenv
WARNING: Skipping virtualenv as it is not installed.
$ sudo apt-get purge python-virtualenv
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package 'python-virtualenv' is not installed, so not removed
0 upgraded, 0 newly installed, 0 to remove and 136 not upgraded.
$ virtualenv --version
virtualenv 20.4.3 from /home/manu/.local/lib/python3.8/site-packages/virtualenv/__init__.py
pip list并pip3 list提及virtualenv.
此外，此处提到的命令不起作用：
sudo apt-get remove virtualenv sudo apt-get remove --auto-remove virtualenv
sudo apt-get purge python-virtualenv sudo apt-get purge --auto-remove python-virtualenv