Python subprocess.Popen() 错误（没有那个文件或目录）
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Python subprocess.Popen() error (No such file or directory)
提问by user2105632
I am trying to count the number of lines in a file using Python functions. Within the current directory, while os.system("ls")finds the file, the command subprocess.Popen(["wc -l filename"], stdout=subprocess.PIPE) does not work.
我正在尝试使用 Python 函数计算文件中的行数。在当前目录中，os.system("ls")找到文件时，命令subprocess.Popen(["wc -l filename"], stdout=subprocess.PIPE) 不起作用。
Here is my code:
这是我的代码：
>>> import os
>>> import subprocess
>>> os.system("ls")
sorted_list.dat
0
>>> p = subprocess.Popen(["wc -l sorted_list.dat"], stdout=subprocess.PIPE)File "<stdin>", line 1, in <module>
File "/Users/a200/anaconda/lib/python2.7/subprocess.py", line 710, in __init__
errread, errwrite)
File "/Users/a200/anaconda/lib/python2.7/subprocess.py", line 1335, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory
采纳答案by bakkal
You should pass the arguments as a list (recommended):
您应该将参数作为列表传递（推荐）：
subprocess.Popen(["wc", "-l", "sorted_list.dat"], stdout=subprocess.PIPE)
Otherwise, you need to pass shell=Trueif you want to use the whole "wc -l sorted_list.dat"string as a command (not recommended, can be a security hazard).
否则，shell=True如果要将整个"wc -l sorted_list.dat"字符串用作命令，则需要通过（不推荐，可能存在安全隐患）。
subprocess.Popen("wc -l sorted_list.dat", shell=True, stdout=subprocess.PIPE)
Read more about shell=Truesecurity issues here.
在此处阅读有关shell=True安全问题的更多信息。
回答by Antti Haapala
The error occurs because you are trying to run a command named wc -l sorted_list.dat, that is, it is trying to find a filenamed like "/usr/bin/wc -l sorted dat".
发生该错误是因为您正在尝试运行名为 的命令wc -l sorted_list.dat，也就是说，它正在尝试查找名为 like的文件"/usr/bin/wc -l sorted dat"。
Split your arguments:
拆分你的论点：
["wc", "-l", "sorted_list.dat"]
