Re: Aw: Aw: Re: Composer not found problem
If you have a dedicated server (as you say) you should be able to manage it by editing your php.ini file to enable proc_open. Look for disable_functions = line (or enable_functions?)
Anyway, correct way of launching setup.sh is sh ./setup.sh. If you have a dedicated server you can create new users (other than root), give them proper rights and run under that user I guess to avoid the warnings?
Btw, Ctrl+C is way to abort any script right away.