The American Standard Code for Information Interchange (ASCII) defined control-characters including CARRIAGE-RETURN (CR) and LINE-FEED (LF) that were (and still are) used to control the print-position on printers in a way analogous to the mechanical typewriters that preceded early computer printers.
As far as I know, every operating system has a different way to mark the end of line (EOL) character. Commercial operating systems use carriage return for EOL (carriage return and line feed on Wind...
3 The normal version of grep (including grep -P) always outputs a line feed with its match, so if you only have one result (or you only want the final added line feed to be removed), it suffices to simply remove the final character of the output, which you can do by piping it through head -c-1.
I'm forced to conclude that You can't get screen to send Line Feed (LF; \n) instead of Carriage Return (CR; \r), at least not without changing something in the source and recompiling. This question asks how to send LF instead of CR from screen. It doesn't have an answer yet.
GNU sed has no built-in limit on line length; as long as it can malloc () more (virtual) memory, you can feed or construct lines as long as you like. However, recursion is used to handle subpatterns and indefinite repetition.
In a text file, a line break is represented by a LF character (line feed, Ctrl+J, numerical value 10 = 0x0a = 013). Pressing Ctrl + J in Vi would actually have the same effect, but you could bind the two keystrokes to separate commands if you wanted.