Well, rm -rf is a unix command. You need to use the Windows command or you bash on Windows. Bash on windows is by far the easiest solution because you can then use all unix commands as well. This tutorial should help you out for that: https://itsfoss.com/install-bash-on-windows/
If you really want to use the windows command line you need to replace it with this line
rd /s /q "node_modules"
source: https://stackoverflow.com/questions/97875/rm-rf-equivalent-for-windows