Python subprocess.Popen()错误(没有这样的文件或目录) [英] Python subprocess.Popen() error (No such file or directory)
问题描述
我正在尝试使用Python函数计算文件中的行数.在当前目录中,当os.system("ls")
查找文件时,命令subprocess.Popen(["wc -l filename"], stdout=subprocess.PIPE
)不起作用.
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.
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
推荐答案
您应将参数作为列表传递(推荐):
You should pass the arguments as a list (recommended):
subprocess.Popen(["wc", "-l", "sorted_list.dat"], stdout=subprocess.PIPE)
否则,如果要将整个"wc -l sorted_list.dat"
字符串用作命令,则需要传递shell=True
(不建议这样做,可能会导致安全隐患).
Otherwise, you need to pass shell=True
if you want to use the whole "wc -l sorted_list.dat"
string as a command (not recommended, can be a security hazard).
subprocess.Popen("wc -l sorted_list.dat", shell=True, stdout=subprocess.PIPE)
在此处shell=True安全问题的信息.
Read more about shell=True
security issues here.
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