alternative is the use of \n
Serial.print("first line\n second line\n");
Besides \n the \t (tab is also interesting as it allows to columnize numbers and text in the output (copy to Excel is a breeze;).
Thanks robtillaart! In fact I was doing a temperature logging project a while ago and I couldn't understand what "/n" means in other people's code examples. I worked with Excel as well in my project so your comment is very useful to me.
I didn't know nothing about "\t" at all, I always was searching for something similar to it.
Appreciate your help!