sudo rosdep init出现的错误

在系统上安装ROS　

在运行

　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

分析原因：国内的长城防火墙，对数据进行了拦截无法获取

解决方案１：

　　使用手机热点。

　　sudo rosdep init　

　　rosdep update

　　总体的消耗的流量不多，并且一直成功。

解决方案２：

　　手动添加/etc/ros/rosdep/sources.list.d/20-default.list

　　在终端输入：

　sudo mkidr -p /etc/ros/rosdep/sources.list.d

   cd  /etc/ros/rosdep/sources.list.d

 　sudo gedit 20-default.list

　　添加如下内容：

　

# os-specific listings first
yaml https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml osx

# generic
yaml https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/base.yaml
yaml https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/python.yaml
yaml https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/ruby.yaml
gbpdistro https://raw.githubusercontent.com/ros/rosdistro/master/releases/fuerte.yaml fuerte

# newer distributions (Groovy, Hydro, ...) must not be listed anymore, they are being fetched from the rosdistro index.yaml instead

之后运行：

　rosdep update

在运行的过程之中，也许还是会出现外网连接失败，这个时候强烈建议使用“手机热点”