In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: “ The first procedure is to create a world file and save it with the .world file extension.”

A block of code is set as follows:

<xacro:include filename=”$(find chefbot_description)/urdf/chefbot_gazebo.urdf.xacro”/> 
<xacro:include filename=”$(find chefbot_description)/urdf/chefbot_properties.urdf.xacro”/> 

Any command-line input or output is written as follows:

$ roslaunch chefbot_gazebo chefbot_empty_world.launch

New terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes for example, appear in the text like this: “ we can command the robot to navigate to some position on the map using the 2D Nav Goal button”.