The reason you're not supposed to parse ls output doesn't have to do with the default formatting; I'm quite sure all widely used implementations of ls have alwa

The reason you're not supposed to parse ls output doesn't have to do with the default formatting; I'm quite sure all widely used implementations of ls have always printed the equivalent of "ls -1" when the output is directed to a non-tty. The actual problem is that UN*X paths can contain all printable characters, including newlines, so if you don't plan to place additional restrictions on the file names you support, you can't at any point parse ls. Of course, ls does more than just list file names so it can be tempting to utilise its features. coreutils ls has (relatively) recently received an additional output format that can be unambiguously parsed, but that's as far as the portability goes.