str2time(str[,zone])
Converts the time specified as a string in the first parameter into the
number of seconds since epoch. This function recognizes a wide variety of formats,
including RFC 1123 (standard HTTP), RFC 850, ANSI C asctime, common log file
format, Unix ls -l, and Windows dir, among others. When a time zone is not
implicit in the first parameter, this function will use an optional time zone
specified as the second parameter, such as "-0800" or "+0500" or "GMT". If the
second parameter is omitted and the time zone is ambiguous, the local
time zone is used.