Search this site   Matching against multi-line strings  Up until
now, we haven't mentioned the issue of multi-line strings. It is
perfectly valid and useful to match against a string containing
several lines, separated by one of the usual line separators.
However, there are a couple of complications:    • The multiple
lines may or may not have a logical meaning. For example, in
HTML or XML, line breaks in the file are actually uninteresting
in most cases. On the other hand, in some other types of file,
line breaks are significant, and we may want to perform an
operation such as finding 'one number per line' or 'the word at
the start of the line';   • Line breaks can be signalled by
different control characters. On UNIX systems, it is typical to
signal a line break with a single ACSII character 10. Windows,
on the other hand, still maintains the tradition of combining
both carriage return (character 13) and newline character. This
is why if you've had the misfortune to use Windows Notepad to
open a README file