And thanky you for the speedy response, it was greatly appreciated! =)
Ok, I guess I got it. I'm using Devtoolset-7 and rbenv 2.5.3, also in CentOS 6.10. Since you couldn't reproduce the error, I tried some extra investigation locally, assuming FRUIT basic inner workings are fine. I think I understood the problem. I had fruit directory in a folder shared between the VM (VirtualBox) and the host, which requires that the user belongs to a specific group (vboxsf, vboxusers) to be able to access this folder. It seems to be related to that. Naturally, my user (as well as...
Fail to install fruit_processor_gem on CentOS 6 (VM)