What is "seconds with milliseconds resolution"

[Santiago Vila]

On Wed, Sep 21, 2016 at 11:19:43AM +0100, Mark McDonnell wrote:

> I'm not sure I really understand the `msec` embedded variable.
> 
> I'm getting the value back as `1474452771.178`

That would be the number of seconds since the "epoch" (1970-01-01 00:00 UTC),
similar to "date +%s" but more accurate.

> It's described as "seconds with milliseconds resolution", but I'm not sure
> what that really means (maths isn't a strong skill for me).

It just means the number is a number of seconds (i.e. the second is
the unit of measure), and you can expect the number to have three
decimal places after the point.

> How do I convert the number into seconds?

The number is already in seconds :-)