捕获由Makefile启动的后台进程的PID [英] Capturing the PID of a background process started by a Makefile

问题描述

我有一个启动Django Web服务器的Makefile.我希望服务器在后台启动，并将PID保存到文件中.

I have a Makefile that starts a Django web server. I would like the server to be started in the background, with the PID saved to a file.

我的食谱如下:

run: venv
    @"${PYTHON}" "${APP}/manage.py" runserver 80

直观地讲，要使该过程成为背景并捕获PID，我必须执行以下操作:

Intuitively, to background the process and capture the PID, I'd have to do something like this:

run: venv
    @"${PYTHON}" "${APP}/manage.py" runserver 80 & ; echo "$$!" > "${LOGDIR}/django.pid"

这是行不通的.当您使用以下命令时，"make"使用的子外壳(在我的情况下为/bin/sh)有效:

This doesn't work, though. The sub-shell that 'make' uses (/bin/sh in my case) works when you use:

<command> &

...为流程提供背景，并在使用时起作用:

...to background a process, and works when use:

<command> ; <command>

(或<command> && <command>等)来链接命令.但是，当我尝试后台处理第一个进程并链接第二个进程时，出现以下错误:

(or <command> && <command>, etc...) to chain commands. However, when I try to background the first process and chain a second one, I get the following error:

/bin/sh: -c: line 0: syntax error near unexpected token `;'

使进程后台并在Makefile中捕获PID的最佳方法是什么?

What is the best way to background a process and capture the PID in a Makefile?

谢谢
-B

推荐答案

只需留下一个&"号，后面不要使用分号:

Just leave a single ampersand, without a semicolon after it:

run: venv
    @"${PYTHON}" "${APP}/manage.py" runserver 80 & echo "$$!" > "${LOGDIR}/django.pid"

Ampersand用作命令分隔符，与分号相同:

Ampersand acts as command separator in the same way as a semicolon:

<command> & <command>

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