Python 弹出命令.等到命令完成

Python popen command. Wait until the command is finished(Python 弹出命令.等到命令完成)

问题描述

我有一个脚本，我用 popen 一个 shell 命令启动.问题是脚本不会等到 popen 命令完成并立即继续执行.

I have a script where I launch with popen a shell command. The problem is that the script doesn't wait until that popen command is finished and go continues right away.

om_points = os.popen(command, "w")
.....

如何告诉我的 Python 脚本等到 shell 命令完成?

How can I tell to my Python script to wait until the shell command has finished?

推荐答案

根据您希望如何处理脚本，您有两种选择.如果您希望命令在执行时阻止而不做任何事情，您可以使用 subprocess.call.

Depending on how you want to work your script you have two options. If you want the commands to block and not do anything while it is executing, you can just use subprocess.call.

#start and block until done
subprocess.call([data["om_points"], ">", diz['d']+"/points.xml"])

如果你想在它执行的时候做一些事情或者把事情输入到 stdin 中，你可以在 popen 调用之后使用 communicate.

If you want to do things while it is executing or feed things into stdin, you can use communicate after the popen call.

#start and process things, then wait
p = subprocess.Popen([data["om_points"], ">", diz['d']+"/points.xml"])
print "Happens while running"
p.communicate() #now wait plus that you can send commands to process

如文档中所述，wait 可能会死锁，因此建议进行交流.

As stated in the documentation, wait can deadlock, so communicate is advisable.

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