If you're not comfortable editing files: DON'T! Leave it enabled in R&D mode, or switch to and from when you require it.

Commenting lines out of /usr/sbin/gainroot is much more "dangerous" (in terms of leading to a complete reflash) than anything else, IMHO.

To repeat: if you need to ask "can you help me clarify what to comment out"[1] then leave it alone!

HTH,

Andrew

[1] I'm not saying you shouldn't be helped to learn how to get around in Linux, or learn shell scripting - but /usr/sbin/gainroot is entirely the wrong file to be playing with.