Date and Time Formats

ISO 8601

   Year:
      YYYY (eg 1997)
   Year and month:
      YYYY-MM (eg 1997-07)
   Complete date:
      YYYY-MM-DD (eg 1997-07-16)
   Complete date plus hours and minutes:
      YYYY-MM-DDThh:mmTZD (eg 1997-07-16T19:20+01:00)
   Complete date plus hours, minutes and seconds:
      YYYY-MM-DDThh:mm:ssTZD (eg 1997-07-16T19:20:30+01:00)
   Complete date plus hours, minutes, seconds and fractional seconds
      YYYY-MM-DDThh:mm:ss.sTZD (eg 1997-07-16T19:20:30.45+01:00)

   where:
      YYYY = four-digit year
      MM   = two-digit month (01=January, etc.)
      DD   = two-digit day of month (01 through 31)
      hh   = two digits of hour (00 through 23) (am/pm NOT allowed)
      mm   = two digits of minute (00 through 59)
      ss   = two digits of second (00 through 59)
      s    = one or more digits representing a decimal fraction of a second
      TZD  = time zone designator (Z or +hh:mm or -hh:mm)

HTTP

   Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 822, updated by RFC 1123
   Sunday, 06-Nov-94 08:49:37 GMT ; RFC 850, obsoleted by RFC 1036
   Sun Nov  6 08:49:37 1994       ; ANSI C's asctime() format

perl print scalar(localtime)

   Tue Mar 20 04:16:25 2007

unix date command

   Tue Mar 20 09:19:18 CDT 2007

RFC-822 format (GNU date -R)

   Tue, 20 Mar 2007 09:21:13 -0500

HL7 Timestamp (DateTime) Format

   YYYY[MM[DD[HHMM[SS[.S[S[S[S]]]]]]]][+/-ZZZZ]^
   note: this is ISO 8824-1987, which is withdrawn