executable named turtlesim_node Mac El Captain

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I am trying to install Indigo on El Captain via home-brew, everything seems to be fine until I try to run turtlesim? Anyone can help here?

> Hangs-MBP:turtlesim Hang$ rosrun turtlesim turtlesim_node [rosrun] Couldn't find executable named turtlesim_node below /Users/Hang/ros_catkin_ws/src/ros_tutorials/turtlesim

I also tried rosmake which ran successfully and I also source my setup.sh, but the error remains.