Powerline secrets

You know that XKCD comic where the protagonist googles a tech question and the only matching result is from a long dead thread or even forum that details the issue but provides no answers? I am wondering if other people sometimes happen on the subcategory of that where the thread originator instead of being DenverCoder9 is… yourself. Instead of “closeness to another soul”, it just engenders a slight disappointment. Right, I’ve been here before, trying the same thing and given up.

Trying to customize my powerline setup raised a number of questions that I could not find answers to in the official documentation, including the question of whether root’s bash prompt could be coloured anything other than fire engine red. Luckily I found answers to all of these this time round.