Vim uses 256 colors if the terminal supports them.

Configured using advice from the Vim Tips Wiki.
http://vim.wikia.com/wiki/256_colors_in_vim
Consolidate terminal settings in vimrc.
Convenience function to run the object code dissassembler.
fish_greeting doesn't error if executables aren't found.

If a command substitution evaluates to nothing, then no argument is
available for the command consuming that substitution value.
e.g. 'test -x (which /usr/bin/bogus) ; echo $status' returns 0.

Fixed by assigning the command substitution result to a local variable,
and testing that value.

Source:
http://sourceforge.net/p/fish/mailman/message/29584569/