Summary
Most of the time, you need the latest version of a package, though sometimes only a specific version will work.
Install a Package
pip install package-name
Install from a Git Repository
pip install git+https://github.com/scrapy/scrapyd-client.git
Upgrade a Package
pip install --upgrade package-name
Install a Specific Version
pip install Pillow==5.3.0
Uninstall a Package
pip uninstall package-name
List Installed Packages
pip list
Show Package Information
pip show package-name
Freeze Installed Packages (for requirements.txt)
pip freeze > requirements.txt
Install from requirements.txt
pip install -r requirements.txt
Check for Outdated Packages
pip list --outdated