It would certainly be possible to whip together something in Python to query a URL to see when it was last modified, using the HTTP headers, but I wondered if there is an existing tool that can do that for me? I'd imagine something like:
% checkurl http://unix.stackexchange.com/questions/247445/ Fri Dec 4 16:59:28 EST 2015
% checkurl "+%Y%m%d" http://unix.stackexchange.com/questions/247445/ 20151204
as a bell and/or whistle. I don't think that wget or curl have what I need, but I wouldn't be surprised to be proven wrong. Is there anything like this out there?