在 Python 中使用`subprocess` 编写 bash for 循环的正确方法 [英] Correct way in Python to write a bash for loop with `subprocess`

问题描述

在另一个SO问题中，我看到了这个编写 for 循环时 bash 的语法在 Python 中似乎不起作用:

In this other SO question I saw that this syntax of bash when writing a for loop doesn't seem to work in Python:

~ $ for num in {2..4}; do echo $num; done
2
3
4

因为不是 4 次不同的迭代，它只执行一个:

As instead of 4 different iterations, it does a single one:

>>> print(subprocess.check_output("for num in {2..4}; do echo $num; done", shell=True).decode())
{2..4}

为什么 Python 不支持这种语法?

Why is it this syntax is not supported in Python?

我看到确实支持其他语法:

I see this other syntax is indeed supported:

>>> print(subprocess.check_output("for num in 2 3 4; do echo $num; done", shell=True).decode())
2
3
4

推荐答案

发布 How to use the bash shell with Python's subprocess module 而不是/bin/sh 表明它使用 /bin/sh 但你可以使用 executable='/bin/bash' 改变它

Post How to use the bash shell with Python's subprocess module instead of /bin/sh shows that it uses /bin/sh but you can use executable='/bin/bash' to change it

import subprocess

print(subprocess.check_output("for num in {2..4}; do echo $num; done", shell=True, executable='/bin/bash').decode())

<小时>

最终你可以使用 bash -c "command"

import subprocess

print(subprocess.check_output('bash -c "for num in {2..4}; do echo $num; done" ', shell=True).decode())

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