bash

bind "set completion-ignore-case on"
bind "set mark-symlinked-directories on"

I’ve been using completion-ignore-case for a while, it auto completes without taking case into account. This is great most of the time, but one issue that comes up every now and then is that using wild cards will only match the specified case, that is c* will only match files starting with a lowercase c, so the command will have to be invoked with both c* and C*.