+brew_prefix=`brew --prefix`
+
+if [ -f /Library/LaunchDaemons/homebrew.mxcl.canna.plist ]
+then
+ sudo launchctl unload -w /Library/LaunchDaemons/homebrew.mxcl.canna.plist
+fi
+if [ -x ${brew_prefix}/sbin/cannakill ]
+then
+ sudo ${brew_prefix}/sbin/cannakill
+fi
+
+(cd ${brew_prefix}; git pull https://github.com/chise/homebrew/)