获取其输出通过管道传递的命令的pid [英] Get the pid of a command whose output is piped

问题描述

为了远程启动程序，请记录其输出并立即查看该日志，我正在使用此脚本:

In order to remotely start a program, log its output and immediately see that log, I'm using this script:

nohup mycommand 2>&1 | tee -a server.log &

现在，我想将新启动的mycommand的pid存储在文件中(其名称非常通用，我不能仅使用pgrep，否则会发生冲突).

Now, I would like to store in a file the pid of the newly started mycommand (whose name is very generic, I can't just use pgrep as there would be a risk of collision).

如果我只添加 echo $！>mycommand.pid 我得到 tee 的pid.

If I just add echo $! > mycommand.pid I get the pid of tee.

如何可靠地将 mycommand 的pid写入文件?

How can I reliably write the pid of mycommand to a file ?

顺便说一句，为什么没有给出正确的pid?

And by the way, why doesn't this give the right pid ?

( nohup mycommand 2>&1 ; echo $! > mycommand.pid ) | tee -a server.log &

推荐答案

好的，这个简单的变体可以工作:

OK, this simple variant works :

( nohup mycommand 2>&1 & echo $! > mycommand.pid ) | tee -a server.log &

我不确定; 为何不起作用，以及为什么我必须使用& 代替.

I'm not sure why the ; didn't work and why I have to use & instead.

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