Python package manager.

# To install a package:
pip3 install <package_name>

# To install a specific version of a package:
pip3 install <package_name>==<package_version>

# To upgrade a package:
pip3 install --upgrade <package_name>

# To uninstall a package:
pip3 uninstall <package_name>

# To save the list of installed packages to a file:
pip3 freeze > <requirements.txt>

# To install packages from a file:
pip3 install --requirements <requirements.txt>

# To show installed package info:
pip3 show <package_name>