Python：在subprocess.Popen（..）中导出环境变量 [英] Python: Exporting environment variables in subprocess.Popen(..)

问题描述

我在调用 subprocess.Popen 时设置一个环境变量有问题。环境变量似乎没有被设置。关于如何正确设置Python命令行调用的环境变量的任何建议？

I am having an issue with setting an environment variable on a call to subprocess.Popen. The environment variable does not seem to be getting set. Any suggestions on how to properly set environmental variables for a Python commandline call?

我的目标是运行一个使用从我的Python代码确定的环境变量的脚本： p>

My goal is to run a script that uses an environmental variable determined from my Python code:

d = dict(os.environ)
d["TEST_VARIABLE"] = str(1234)
subprocess.Popen('/usr/bin/mybinary', env=d).wait()

但是脚本反应就好像变量从未被设置

but the script reacts as if the variable has never been set

这是我尝试使用Python的交互式解释器进行测试：

Here is my attempt to test, using Python's interactive interpreter:

d = dict(os.environ)
d["TEST_VARIABLE"] = str(1234)
subprocess.Popen(['/bin/echo', '$TEST_VARIABLE'], env=d).wait() 

，输出为：

"$TEST_VARIABLE"
0

我以为 env = d 应该为子进程设置环境，但是显然没有。关于如何纠正这个问题的任何建议？

I thought env=d should set the environment for the subprocess, but it apparently does not. Any suggestions on how to correct this issue?

推荐答案

在命令行上替换环境变量由shell完成，而不是由/斌/回声。所以你需要在一个shell中运行命令来获得替换：

The substitution of environment variables on the command line is done by the shell, not by /bin/echo. So you need to run the command in a shell to get the substitution:

In [22]: subprocess.Popen('/bin/echo $TEST_VARIABLE', shell=True, env=d).wait()
1234
Out[22]: 0

然而，这并不意味着环境变量在 shell = False 时未设置。即使没有 shell = True ，可执行文件也会看到由 env 参数设置的环境变量。例如， date 受 TZ 环境变量的影响：

That doesn't mean the environment variable is not set when shell=False, however. Even without shell=True, the executable does see the enviroment variables set by the env parameter. For example, date is affected by the TZ environment variable:

In [23]: subprocess.Popen(["date"], env={'TZ': 'America/New_York'}).wait()
Wed Oct 29 22:05:52 EDT 2014
Out[23]: 0

In [24]: subprocess.Popen(["date"], env={'TZ': 'Asia/Taipei'}).wait()
Thu Oct 30 10:06:05 CST 2014
Out[24]: 0

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