blueyed's ZSH-fu is much stronger than mine.

2717e147 · Theodore Robert Campbell Jr · Robby Russell · 8ed33a8c · 2717e147
Commit 2717e147 authored Mar 02, 2011 by Theodore Robert Campbell Jr Committed by Robby Russell Apr 12, 2011
--- a/plugins/hub/hub.plugin.zsh
+++ b/plugins/hub/hub.plugin.zsh
 # hub alias from defunkt
 # https://github.com/defunkt/hub
-if [ $( which hub > /dev/null 2>&1 ; echo -n $? ) -lt 1 ]; then
+if which hub > /dev/null; then
-    eval $( hub alias -s zsh )
+    eval $(hub alias -s zsh)
 fi