'\r' is just a another ASCII code character. By definition it is a CR or carriage return. It's the terminal or console being used that will determine how to interpret it. Windows and DOS systems usually expect every line to end in CR/LF ('\r\n') while Linux systems are usually just LF ('\n'), classic Mac was just CR ('\r'); but even on these individual systems you can usually tell your terminal emulator how to interpret CR and LF characters.
Historically (as a typewriter worked), LF bumped the cursor to the next line and CR brought it back to the first column.
To answer the question about why nothing is printing: remove the comma at the end of your print line.