bash等待进程结束

目标

要等待某个进程执行完毕以后，再执行后续操作。

脚本

下面脚本实现了等待某个进程执行完毕，然后等待期间打印当前时间，进程执行完毕以后关机

while ps -p 2261 >/dev/null;do echo "still processing $(date +%Y-%m-%d\ %H:%M:%S)" && sleep 2;done;poweroff

等待期间的输出

still processing 2020-02-29 10:36:31
still processing 2020-02-29 10:36:33
still processing 2020-02-29 10:36:35
still processing 2020-02-29 10:36:37
still processing 2020-02-29 10:36:40
still processing 2020-02-29 10:36:42
still processing 2020-02-29 10:36:44
still processing 2020-02-29 10:36:46
still processing 2020-02-29 10:36:48
still processing 2020-02-29 10:36:50
still processing 2020-02-29 10:36:52
still processing 2020-02-29 10:36:54
still processing 2020-02-29 10:36:56
still processing 2020-02-29 10:36:58
still processing 2020-02-29 10:37:00
still processing 2020-02-29 10:37:02
still processing 2020-02-29 10:37:04
still processing 2020-02-29 10:37:06
still processing 2020-02-29 10:37:08
still processing 2020-02-29 10:37:10
still processing 2020-02-29 10:37:12
still processing 2020-02-29 10:37:14
still processing 2020-02-29 10:37:16
still processing 2020-02-29 10:37:18
still processing 2020-02-29 10:37:20
still processing 2020-02-29 10:37:22
still processing 2020-02-29 10:37:24