react-native init 'app-name' / react-native run-ios - command not found

[Deasse]

I installed react-native for iOS (not using the quick start method with expo) following the steps on the react native page: https://facebook.github.io/react-native/docs/getting-started.html

The steps include also installing the cli globally (I also tried it installing it locally, by leaving out the -g in the command)

After running

react-native init newapp

the terminal responds with 'command not found'

• Here so far -

however I can initialize a new app and reopen apps (/the command is found here) only and only after exporting the path where the react-native cli has been installed. For reference see this post here:

https://stackoverflow.com/questions/37189081/react-native-command-not-found?noredirect=1&lq=1

I strongly assume that the npms and the cli of react-native are on different paths where they can not connect properly...

I think it's also worth mentioning that the terminal shows me:
Unhandled rejection Error: EACCES: permission denied, mkdir '/Users/username/.npm/_cacache/index-v5/de/62'

,when initializing a new app with the export method...

--I also have an older Mac where all seems to work out smoothly...--

Any ideas?
Thanks in advance 👊✌🏾