Commands:

-n, --now

Display the current date/time

-d, --date=value

Parse an ISO8601 date/time. Eg. '2005-01-20 00:30:00 +01:00' or '2005-040'

-p, --period=value

Parse an ISO8601 period (interval) with start time (for example, '2005-040/2005-043')

-D, --duration=value

Parse an ISO8601 duration with start time (for example, '2005-040/P1M')

-E, --expected=value

Parse an ISO8601 duration with start time (for example, '2005-040/P1M')

Output Modifiers:

-s, --seconds

Show result as a seconds since 0000-001 00:00:00Z

-S, --epoch

Show result as a seconds since EPOCH (1970-001 00:00:00Z)

-L, --local

Show result as a 'local' date/time

-O, --ordinal

Show result as an 'ordinal' date/time

-W, --week

Show result as an 'calendar week' date/time

For more information on the ISO8601 standard, see: http://en.wikipedia.org/wiki/ISO_8601