Django: run a Unix command from with Django?

Sorry if this is a duplicate - couldn't find an answer by searching.

How can I run a Unix command from within a Django views file? I want to run a 'cp' command to copy a file that's just been uplo开发者_如何学Caded.

Thanks in advance.

Why command line cp?

Use Python's builtin copyfile() instead. Portable and much less error-prone.

import shutil
shutil.copyfile(src, dest)

In fact, the preferred way to run system program is to use the subprocess module, like:

import subprocess    
subprocess.Popen('cp file1 file2',shell=True).wait()

Subprocess module is a replacement for os.system and other older modules and functions, see http://docs.python.org/library/subprocess.html

Of course if you need just to copy files you may use more convenient function copyfile from shutil module

In Python:

import os
if os.system("cp file1 file2") == 0:
    # success
else:
    # failure

I would use iterpipes, which reduces the 'By Hemidall's beard, what foul syntax!' one tends to think when working with subprocess.

I'd recommend subprocess.Popen() for the general case. It's more flexible than os.system().

It's better to use Popen/PIPE for that kind of stuff.

from subprocess import Popen, PIPE

def script(script_text):
     p = Popen(args=script_text,
               shell=True,
               stdout=PIPE,
               stdin=PIPE)

     output, errors = p.communicate()
     return output, errors

script('./manage.py sqlclear my_database_name')  

I would not recommend using os.system since it has got a number of limitations.

As Python documentation says:

This is implemented by calling the Standard C function system(), and has the same limitations. Changes to sys.stdin, etc. are not reflected in the environment of the executed command.