In some of the example listings, what is meant to be displayed on one line does not fit inside the available page width. These lines have been broken up. A '\' at the end of a line means that a break has been introduced to fit in the page, with the following lines indented. So:

Let's pretend to have an extremely \
long line that \
does not fit
This one is short

Is really:

Let's pretend to have an extremely long line that does not fit
This one is short