Unix systems, the end of each line only "<wrapping>", namely "\ the n-"; Windows system which, at the end of each line is "<line feed> <Enter>", namely "\ n \ r"; Mac system, the end of each line is "<Enter>." A direct consequence is that the files under Unix / Mac system opened in Windows, then all the text will become a line; and Windows in the file opened under Unix / Mac, then at the end of each line might be more of a ^ M symbol.
front \ r carriage is to move the cursor one line
\ n to the next line is
