Python无法识别大于号吗？

Question

I am using Python to create windows commands using subprocess.call(command) where command is a string I've generated for the Windows command. I need the results of my command to output to a .txt file so I use 2>> C:\\Users\\me\\out.txt as part of command except Python does not seem to recognize the greater than character, > . I've tried using the Unicode value, u'\>' too.

[EDIT] If I copy command and paste it into my command prompt, then it will execute the command properly. Otherwise it won't work from my Python script.

Answer 1

Python has nothing to do with that.

If you do

subprocess.call("command 2>>out.txt", shell=True)

it is the shell which does this part of redirection.

If you don't work with the shell, it cannot work. In this case, you better do

with open("out.txt", "a") as outfile:
    subprocess.call(["command"], stderr=outfile)

Answer 2

如果使用的是诸如重定向之类的外壳结构，则需要参数shell=True 。