This chapter is from the book
Long Command Lines
Long command lines are automatically scrolled by Bash: When your cursor reaches the right-hand side of the window, Bash continues the command on the next line.
If you want to break up a command so that it fits on more than one line, use a backslash (\) as the last character on the line. Bash will print the continuation prompt, usually a >, to indicate that this is a continuation of the previous line.
$ printf "%s\n" "This is a very long printf. How long is it?\ > It's so long that I continued it on the next line." This is a very long printf. How long is it? It's so long that I continued it on the next line.