Unix/Linx 系统中所有时间相关的处理函数的总结(包括获取设置系统时间,带时区不带时区时间以及不同格式的时间字符串)-Unix/Linx system processing functions all the time-related summary (including access to set the system time with time zone with no time zone and time strings in different formats)

三个时区的倒计时牌，可以切换时区，初学者编。-Three time zones of the countdown board, to switch time zones, beginners series.