Decoded: GNU Coreutils
Or, just browse the originals:https://www.tuhs.org/cgi-bin/utree.pl?file=V7/usr/src
https://www.tuhs.org/cgi-bin/utree.pl?file=4.3BSD/usr/srcand some of their current decedents:https://svnweb.freebsd.org/
http://cvsweb.openbsd.org/cgi-bin/cvsweb/
http://cvsweb.netbsd.org/bsdweb.cgi/src/?only_with_tag=MAIN
https://gitweb.dragonflybsd.org/dragonfly.gitconveniently all in one source tree, self hosting, and buildable with a single command.it is almost as if they were designed as part of a single coherent operating system along with the very C language itself..as discussed previously, typically with more intelligible sources:https://news.ycombinator.com/item?id=14542938and usually with better man pages (https://www.freebsd.org/cgi/man.cgi)unix came first. gnu and posix came later.the unix way is the standard, not posix, and not gnu.from stallman himself (https://stallman.org/articles/posix.html):"
It seemed to me that nobody would ever say "IEEEIX", since the pronunciation would sound like a shriek of terror; rather, everyone would call it "Unix". That would have boosted AT&T, the GNU Project's rival, an outcome I did not want. So I looked for another name, but nothing natural suggested itself to me.So I put the initials of "Portable Operating System" together with the same suffix "ix", and came up with "POSIX". It sounded good and I saw no reason not to use it, so I suggested it. Although it was just barely in time, the committee adopted it. 
"so, as can be seen, posix is RMS's way of keeping people from calling unix unix, 
and as a result today, now that AT&T Unix is nearly dead,
people lose track of the fact that BSD is Unix, and don't know what Unix actually is, and are forced to 'decode' the sometimes deliberately less clear cloned sources not knowing to look at the simpler original.