ago

Subtracts an interval of time from the current object’s time and returns the result as a new TimeWithZone object.

Time.zone = 'Eastern Time (US & Canada)' # => 'Eastern Time (US & Canada)' now = Time.zone.now # => Mon, 03 Nov 2014 00:26:28.725182881 EST -05:00 now.ago(1000) # => Mon, 03 Nov 2014 00:09:48.725182881 EST -05:00 

If we’re subtracting a Duration of variable length (i.e., years, months, days), move backward from #time, otherwise move backward from #utc, for accuracy when moving across DST boundaries.

For instance, time.ago(24.hours) will move back exactly 24 hours, while time.ago(1.day) will move back 23-25 hours, depending on the day.

now.ago(24.hours) # => Sun, 02 Nov 2014 01:26:28.725182881 EDT -04:00 now.ago(1.day) # => Sun, 02 Nov 2014 00:26:28.725182881 EDT -04:00