[jbarber]

I like to use (for GNU date at least): $ date -Iseconds 2011-11-21T10:56:17+0000

because it requires less typing. The ISO 8601 standard format.

-Is, -Im, -Ih, and -Id allow you to change the displayed resolution.

Bizarrely, this doesn't seem to be documented in my version of date (coreutils 8.10).

[dredmorbius]

A lot of the date documentation is unfortunately in info only. Debian (and derived distros) do a good job of updating the manpages.

That said, I can't find "-I" documented anywhere.

What I like about the timestamp I use is that it's semantic but sorts lexically as well. Though yours does as well. Hrm.