I stumbled on the NewLine article on wikipedia
today during some random browsing, and I never expected it to be so fascinating.
It shows some interesting history, and how many different Operating Systems have different control characters to represent a new line, and for different reasons.
There is also some confusion as to whether newlines terminate or separate lines. If a newline is considered a separator, there will be no newline after the last line of a file. The general convention on most systems is to add a newline even after the last line, i.e., to treat newline as a line terminator. Some programs have problems processing the last line of a file if it isn't newline terminated. Conversely, programs that expect newline to be used as a separator will interpret a final newline as starting a new (empty) line. This can result in a different line count being reported for the file, but is otherwise generally harmless.
wow... I never even thought about it that way. I guess it can be interpreted both as a separator and as a terminator. I can see how some interoperability problems could occur. This is one of those things that, when I really think about it, makes me realize that it's a small miracle that software as we have it today works at all! - When programs can't even agree on what a new line is, or even how to treat it.
It doesn't stop there, the problem persists on our internets:
Most textual Internet protocols (including HTTP, SMTP, FTP, IRC and many others) mandate the use of ASCII CR+LF (0x0D 0x0A) on the protocol level, but recommend that tolerant applications recognize lone LF as well. In practice, there are many applications that erroneously use the C newline character '\n' instead (see section Newline in programming languages below). This leads to problems when trying to communicate with systems adhering to a stricter interpretation of the standards; one such system is the qmail MTA that actively refuses to accept messages from systems that send bare LF instead of the required CR+LF.