CommandHelper has a built in logger, which allows for subsystems to be individually monitored and logged. There are various settings that affect what data is logged, and how it is shown. There are two steps to configuring the logger, but reasonable defaults have been selected for you. To change the main settings, go to logs/debug/loggerPreferences.txt, which is the configuration settings for the logger. You can adjust settings on the individual subsystems from here.
In addition, if a message would be logged to file, depending on other settings, it will also be displayed on screen. The following rules apply if the message is set to be logged based on your settings:
If debug mode is on, all messages are logged to the screen too. If show-warnings is true, warnings and errors are shown on screen. Otherwise, just error messages are shown on screen. Assuming your preferences are set correctly, the console will color code the output as well.