You can, pretty easily, get a UNIX timestamp (time since the epoch, January 1, 1970, at 0:00:00), with
date +%s. But how the heck do you do it in reverse? Given a timestamp like
1415744430, how do you convert that to a more conventional format?
My answer has always been “use a tool online”, or to pull up an interactive shell in something like Ruby. But there has to be a better way, right?
There is! But, it’s not standard.
On a Linux box (GNU coreutils)
$ date -d @1415744430
Tue Nov 11 22:20:30 UTC 2014
@ is important.
On a Mac OS X box (BSD-derived)
$ date -r 1415744430
Tue Nov 11 17:20:30 EST 2014
So, there you have it, standardization be damned.