Earlier quoted context omitted.
There are two problems I've found that prevent me from using fish more: 1. Fish syntax breaks virtualenv (Edit: Okay, apparently this isn't actually a problem). 2. Fish does not have the equivalent of 'disown' in bash. This is fine if you exit the parent shell normally, but not if you send SIGKILL, which my window manager (wmii and i3) does.
. bin/activate.fish
# This file must be used with ". bin/activate.fish" from fish (http://fishshell.org)*