date(1) - print or set the system date and time
-d, --date=STRING
       display time described by STRING, not `now'
-f, --file=DATEFILE
       like --date once for each line of DATEFILE
-r, --reference=FILE
       display the last modification time of FILE
-R, --rfc-2822
       output date and time in RFC 2822 format.  Example: Mon, 07 Aug 2006 12:34:56 -0600
       output date and time in RFC 3339 format.  TIMESPEC=`date', `seconds', or `ns' for date and time to
       the indicated precision.  Date and time components are separated by  a  single  space:  2006-08-07
-s, --set=STRING
       set time described by STRING
-u, --utc, --universal
       print or set Coordinated Universal Time
--help display this help and exit
       output version information and exit