Haha! I like this post. I do have some criticisms, though:

A single letter doesn't adequately describe the function of the tests. The test names should be longer and more descriptive.

Since Perl was originally intended to be a sort of "shell language for text manipulation" and unix shells also use the -X functions for file tests, the single letter scheme probably made it easy for the intended audience to learn and use them. We can hardly remove it now, as it would break most scripts that need the tests. I agree that the names for these functions should be longer and more descriptive, but that's what File::Stat does for you already, if you want to use it.

The numbering of array indexes and other things in Perl start at 0. This is dumb.

There are perfectly valid arguments for using a 1-based indexing scheme, just as there are perfectly valid arguments for using a 0-based indexing scheme. Since you don't provide any, I won't either. Look around, this discussion has been going on for decades. AFIK most modern (as in, newer) languages use 0-based indexing, though (I'm not saying 0-based indexing is more correct, just that it's become the dominant scheme).

Some other 0-based indexing schemes in Perl are rather silly (like 0-based months) but are here because of consistency with underlying system calls and backward compatibility. OTOH I haven't directly manipulated the output of localtime() and gmtime() in years: I find POSIX::strftime() and the DateTime modules much simpler to use anyway.

Misc. feedback:

I like Ratty.

I'd like to see a discussion about little-endianness vs big-endianness in next issue. :-)