服务器调用的PHP脚本是否异步运行？(Does a server-called PHP script run asynchronously?)

 如果服务器通过命令行（在Ubuntu服务器上）调用PHP脚本，那么该脚本的多个实例是否可以同时运行？ 在我的例子中，它是一个PHP脚本，使用FFmpeg转换上传的视频。 因此，如果八个用户同时（或非常接近）上传视频，那么该PHP脚本的八个实例会同时运行，还是会一个接一个地排队？ 如果他们排队，有没有办法改变它，以便多个实例可以同时运行？ 

If a PHP script is called by the server via command line (on an Ubuntu server), can multiple instances of that script be running at the same time? In my case, it's a PHP script that converts uploaded video using FFmpeg. So if eight users upload a video at the same moment (or very close to it), will eight instances of that PHP script be running simultaneously, or will they queue up, one after another? If they queue up, is there a way to change it so that multiple instances CAN run simultaneously?

原文：https://stackoverflow.com/questions/32429329