while true do cmd(shell 命令) sleep x(x为秒数) done ————————————————版权声明:本文为CSDN博主「这年头起名真难3232」的原创文章,遵循 CC 4.0 BY-SA 版权协议,转载请附上原文出处链接及本声明.原文链接:https://blog.csdn.net/linux_s2018/article/details/80672282…
对于dispatch多个异步操作后的同步方法,以前只看过dispatch_group_async,看看这个方法的说明: * @discussion * Submits a block to a dispatch queue and associates the block with the given * dispatch group. The dispatch group may be used to wait for the completion * of the blocks it ref…