"\n" is unique in that it finishes a line. I think it's for hysterical...errrmmm...historical reason. When something is printed on a lineprinter there is no use in printing each single char. It would last too long to open the connection, print one character, close the connection...
So everything gets buffered until the line is full or is said to be full ("\n" sent) and then the buffer gets printed
$\=~s;s*.*;q^|D9JYJ^^qq^\//\\\///^;ex;print