logr will write all errors and the last warning to the log. Errors are written at the point they are encountered. Warnings will be written at the end of the log.
If errors or warnings are generated, they will also be written to a separate file called a message file. The message file has the same name as the log, but with a .msg extension. The purpose of the message file is so that errors and warnings that occur during execution of the script can be observed from the file system. The presence or absence of the .msg file will indicate whether or not the program ran clean.