I'm not aware of any type of text file, that supports switching line deliminators inside of the same file....
Now that doesn't mean it couldn't exist, but logically that would be a strange file....
I think it's a even bet that a file would have the same deliminator throughout the file.
I have observed this on Windows, where the text editor in VC++ can read files with \n line endings, and doesn't change those when it writes the file back, but always adds \r\n to lines it adds. So if you edit a file containing only \n line endings, inserting a few lines, you have mixed line endings. Also, Java supports this, and the algorithm to support it is not difficult: to read a line, read until you see either \r or \n; if you see \r, peek one character ahead and if that's a \n, include it in the line. (Haven't had the time to read the whole proposal, but a Java style text file implementation has been in my wish list for a long time.) --Guido van Rossum (home page: http://www.python.org/~guido/)