rosdep init and update Error

rosdep init Error

$ sudo rosdep init
ERROR: default sources list file already exists:
/etc/ros/rosdep/sources.list.d/20-default.list
Please delete if you wish to re-initialize
Then you can execute
$ sudo rm /etc/ros/rosdep/sources.list.d/20-default.list
You can continue with
$ sudo rosdep init

rosdep update Error

$ rosdep update
If you get
reading in sources list data from /etc/ros/rosdep/sources.list.d
Hit https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml
Hit https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/base.yaml
ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/python.yaml]:
(https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/python.yaml)
then you can execute the following command:
$ sudo apt-get update
Then you can continue with
$ rosdep update

Further reading

http://answers.ros.org/question/47177/rosdep-update-error/