Swagger is a set of open source tools, like the UI / Editor / Codegen / Parser / etc.
SwaggerHub is an online service aimed at the API lifecycle, user management and persisting the API definitions in your team/organization.
If you're referring to the `swaggerhub` cli tool, it's there to help you upload and manage your SwaggerHub definitions. The restrictions are based on what plan you have. SwaggerHub includes a free plan.
The `swagger` cli tool is connects together several of the js-based Swagger tools. Like the express framework, validation, etc. It is open source and can operate outside of SwaggerHub.
If you'd like to know anything more specific, feel free to ask 🙂