Formatting date in Unix

For mm/dd/yy hh:mm:ss format

$ date +"%m/%d/%y : %r"
08/26/16 : 12:03:52

dd/mm/yy hh:mm:ss format

$ date +"%d/%m/%y : %r"

26/08/16 : 12:04:08

dd/mm/yyyy hh:mm:ss format

$ date +"%d/%m/%Y : %r"

26/08/2016 : 12:12:55

yyyy/mm/dd format

$ date +"%Y/%m/%d"

2016/08/26