> Victor: did you notice that getoutput and friends call os.popen?

Yes, because I wrote a patch to call directly subprocess :-) => see the issue 
#10197. I don't want to remove os.popen() anymore, it's too much work for a 
minor gain (we will remove it in Python 4). But we can add a note in its 
documentation saying that the subprocess should be prefered.

> But that is only true in general, and os.popen was never
> a "thin" wrapper, at least on most platforms.

os.popen() was a thin wrapper in Python 2.x: posix.popen() was a wrapper of 
the popen() C function.