Как говорит википедия:

CR+LF: Microsoft Windows, DEC TOPS-10, RT-11 and most other early non-Unix
       and non-IBM OSes, CP/M, MP/M, DOS (MS-DOS, PC-DOS, etc.), Atari TOS,
       OS/2, Symbian OS, Palm OS
LF+CR: Acorn BBC spooled text output.
CR:    Commodore 8-bit machines, Acorn BBC, TRS-80, Apple II family,
       Mac OS up to version 9 and OS-9
LF:    Multics, Unix and Unix-like systems (GNU/Linux, AIX, Xenix, Mac OS X,
       FreeBSD, etc.), BeOS, Amiga, RISC OS, and

Как резюмирует это stackoverflow:
Windows: '\r\n'
Mac (OS 9-): '\r'
Mac (OS 10+): '\n'
Unix/Linux: '\n'