Calculate date from another time.
(c) 2011-2015 Roman Piták roman@pitak.net
datecalc [OPTIONS]
-p +STRING : set print string
: default : +%Y-%m-%d %H:%M:%S
-Y year : set Year to be used as reference
-M month : set Month to be used as reference
-D day : set Day to be used as reference
-h hour : set Hour to be used as reference
-s second : set Second to be used as reference
-m minute : set Minute to be used as reference
-h : print this help message
--isLeapYear [year] : true if year is a leap year
-l [month] : print number of days in a month
--man : print full manual
-number time_unit : set negative time offset
+number time_unit : set positive time offset
datecalc -1d : print yesterday`s date
datecalc -100 seconds -s "+%Y"
: what was the year 100 seconds ago?
datecalc -Y 1995 -M 08 -D 24 -h 0 -m 0 -s 0 +3M
: print the date 3 months after Win95 release