# If you're trying to get the string into a variable, another easy way is something like this:
USAGE=$(cat <<-END
This is line one.
This is line two.
This is line three.
END
)
#If you indent your string with tabs (i.e., ' '), the indentation will be stripped out. If you indent with spaces, the indentation will be left in.
#NOTE: It is significant that the last closing parenthesis is on another line. The END text must appear on a line by itself.