[REQUEST] Add an environment variable to disable all progress bars

[mtn]

Consider posting in https://github.com/textualize/rich/discussions for feedback before raising a feature request.

Have you checked the issues for a similar suggestions? Yes.

How would you improve Rich?

Please add an environment variable (e.g. DISABLE_RICH) which, when set, disables all progress bars.

What problem does it solve for you?

There's no global way to disable all progress bars that I'm aware of without adding disable=True to every one. When running under a debugger like pdb, this would be very useful.