在终端运行roscore，分别运行rosrun turtlesim turtle和rosrun turtlesim turtle_teleop_key，再输入rqt_graph，提示如下错误
"dot" with args ['-Tdot', '/tmp/tmp145cvdav'] returned code: 1
stdout, stderr:
b''
b'Format: "dot" not recognized. Use one of:\n'
PluginHandlerDirect._restore_settings() plugin "rqt_graph/RosGraph#0" raised an exception:
Traceback (most recent call last):
File "/opt/ros/noetic/lib/python3/dist-packages/qt_gui/plugin_handler_direct.py", line 121, in _restore_settings
self._plugin.restore_settings(plugin_settings_plugin, instance_settings_plugin)
File "/opt/ros/noetic/lib/python3/dist-packages/rqt_graph/ros_graph.py", line 260, in restore_settings
self._refresh_rosgraph()
File "/opt/ros/noetic/lib/python3/dist-packages/rqt_graph/ros_graph.py", line 289, in _refresh_rosgraph
self._update_graph_view(self._generate_dotcode())
File "/opt/ros/noetic/lib/python3/dist-packages/rqt_graph/ros_graph.py", line 308, in _generate_dotcode
解决办法
在终端输入sudo dot -c