Closing files is probably still a good habbit to get into. Consider:
That it documents that you won't be messing with a file anymore.
And if you use flock(), and are into the habbit of NOT closing your files, you could end up with a messy unintentional bottleneck
I did not complained that it's better not to close filehandles, just joke come into my mind (as I marked it).
Mostly I tried to spot bugs in that program. Did you noticed that it will eat first innocent first line from a file?
And, ackohno, to ask your question, yes, I use \r\n=>\n conversion on Win32.
addition and once again: if you forgot that you already used that program, and use it again, it will damage file by eating it from two sides: almost each time will eat a line from top, and each time eat one character from right side.