pip clears the cache and skips the cache when installing modules

When installing a python module with pip, "Using cache" will often appear when a certain module is repeatedly installed, which makes it easy to install the wrong version. So I found about two methods in stackoverflow.

1. Skip the cache directly: (tqdm is chestnut)

pip install -U tqdm

2. Clean up pip cache

cd ~/.cache/pip
sudo rm -rf *

Note: When doing rm, you must see the path clearly, don't delete the library and finally run away.

Reference link: https://stackoverflow.com/questions/9510474/removing-pips-cache