Linux 杀死进程并等待进程退出

Kill a process and wait for the process to exit

提问by woodings

When I start my tcp server from my bash script, I need to kill the previous instance (which may still be listening to the same port) right before the current instance starts listening.

当我从我的 bash 脚本启动我的 tcp 服务器时，我需要在当前实例开始侦听之前终止前一个实例（它可能仍在侦听相同的端口）。

I could use something like pkill <previous_pid>. If I understand it correctly, this just sends SIGTERMto the target pid. When pkillreturns, the target process may still be alive. Is there a way to let pkillwait until it exits?

我可以使用类似的东西pkill <previous_pid>。如果我理解正确，这只会发送SIGTERM到目标 pid。当pkill返回时，目标进程可能仍然活着。有没有办法让它pkill等到它退出？

回答by Roland Jansen

Use wait(bash builtin) to wait for the process to finish:

使用wait(bash builtin) 等待进程完成：

 pkill <previous_pid>
 wait <previous_pid>

回答by Aaron Digulla

No. What you can do is write a loop with kill -0 $PID. If this call fails ($? -ne 0), the process has terminated:

不。你可以做的是用kill -0 $PID. 如果此调用失败 ( $? -ne 0)，则进程已终止：

while kill -0 $PID; do 
    sleep 1
done

(kudos to qbolecfor the code)

（感谢 qbolec的代码）

Related:

有关的：

• What does `kill -0 $pid` in a shell script do?

• shell 脚本中的 `kill -0 $pid` 有什么作用？