>> Of course, if you GNU coreutils on your system (and if you're running Linux, you almost certainly do), it's even easier and more efficient: "comm -23 A B".
Maybe I'm misunderstanding your point, but I don't think GNU's coreutils is the only way to get comm[1].
No, you understood my comment; I assumed since the manpage I was looking at made no reference to a standard, that it was nonstandard. It seems you're right, and comm(1) is more widely available, excellent.
Maybe I'm misunderstanding your point, but I don't think GNU's coreutils is the only way to get comm[1].
Nice update to the original post, by the way. :)
[1] http://pubs.opengroup.org/onlinepubs/9699919799/utilities/co...