You want to know how I know you never wrote your own C program or terminal emulator?
/r means "slash, then the letter r". \r means carriage return, which doesn't clear the line, just moves the cursor to the left margin. Unless you're on an Apple ][, in which case CHR$(13) moves to the beginning of the next line, but still doesn't clear anything. And CHR$(4) is where the real magic happens, but it has to follow a CHR$(13)!