pip on Windows giving the error – Unknown or unsupported command ‘install’

Do you happen to have the Perl pip lying around somewhere?

Sounds like the problem described here:

https://github.com/mike-perdide/gitbuster/issues/62

To check, in Windows command prompt execute:

C:\>where pip

This will potentially output the following:

C:\strawberry\perl\bin\pip
C:\strawberry\perl\bin\pip.bat

If so, this is your problem. Unistall Strawberry Perl or use the full path to python pip.