text following each line matched by
goes over more than one line, newlines must be "hidden" by preceding
them with a backslash. The
text will be terminated by the first
newline that is not hidden in this way. The
not available in the pattern space, and subsequent commands
cannot be applied to it. The results of this command
are sent to standard output when the list of editing commands is finished,
regardless of what happens to the current line in the pattern space.
$a\ This goes after the last line in the file\ (marked by $). This text is escaped at the\ end of each line, except for the last one.