系统到现在多少秒
local time = os.time()
print( time )
给定时间的时，分，秒
local test = os.data( "%X", time )
"%X"是转换格式，类似与lua string中的formart。时间格式如下：
| %a |
abbreviated weekday name (e.g., Wed) |
| %A |
full weekday name (e.g., Wednesday) |
| %b |
abbreviated month name (e.g., Sep) |
| %B |
full month name (e.g., September) |
| %c |
date and time (e.g., 09/16/98 23:48:10) |
| %d |
day of the month (16) [01-31] |
| %H |
hour, using a 24-hour clock (23) [00-23] |
| %I |
hour, using a 12-hour clock (11) [01-12] |
| %M |
minute (48) [00-59] |
| %m |
month (09) [01-12] |
| %p |
either "am" or "pm" (pm) |
| %S |
second (10) [00-61] |
| %w |
weekday (3) [0-6 = Sunday-Saturday] |
| %x |
date (e.g., 09/16/98) |
| %X |
time (e.g., 23:48:10) |
| %Y |
full year (1998) |
| %y |
two-digit year (98) [00-99] |
| %% |
the character '%' |
转载：http://www.cnblogs.com/wodehao0808/p/3935062.html