Comment by blattimwind

I've written a whole bunch of CLI tools over the years and maintained some I didn't author originally, I always found it annoying how slow these are. A CLI tool for some larger project can easily take a second just to display --help, or a command line parse error. Tests running against it can be made to progress faster (no forking, no separate interpreter, in-process capture etc. which brings a lot of complexity and subtle differences and error persistence/"tainting" of the execution environment), but still you might only get a few CLI invocations per second per core.

Theses experience are a major turn-down from Python for me.