Since os.popen is being replaced by subprocess.popen, I was wondering how would I convert

os.popen('swfdump /tmp/ -d')

to subprocess.popen()

I tried:

subprocess.Popen("swfdump /tmp/filename.swf -d")
subprocess.Popen("swfdump %s -d" % (filename)) # NOTE: filename is a variable # containing /tmp/filename.swf

But I guess I'm not properly writing this out. Any help would be appreciated. Thanks

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5 Answers

subprocess.Popen takes a list of arguments:

from subprocess import Popen, PIPE
process = Popen(['swfdump', '/tmp/filename.swf', '-d'], stdout=PIPE, stderr=PIPE)
stdout, stderr = process.communicate()

There's even a section of the documentation devoted to helping users migrate from os.popen to subprocess.

15

Use sh, it'll make things a lot easier:

import sh
print sh.swfdump("/tmp/filename.swf", "-d")

1

In the recent Python version, subprocess has a big change. It offers a brand-new class Popen to handle os.popen1|2|3|4.

The new subprocess.Popen()

import subprocess
subprocess.Popen('ls -la', shell=True)

Its arguments:

subprocess.Popen(args, bufsize=0, executable=None, stdin=None, stdout=None, stderr=None, preexec_fn=None, close_fds=False, shell=False, cwd=None, env=None, universal_newlines=False, startupinfo=None, creationflags=0)

Simply put, the new Popen includes all the features which were split into 4 separate old popen.

The old popen:

Method Arguments
popen stdout
popen2 stdin, stdout
popen3 stdin, stdout, stderr
popen4 stdin, stdout and stderr

You could get more information in Stack Abuse - Robert Robinson. Thank him for his devotion.

It may not be obvious how to break a shell command into a sequence of arguments, especially in complex cases. shlex.split() can do the correct tokenization for args (I'm using Blender's example of the call):

import shlex
from subprocess import Popen, PIPE
command = shlex.split('swfdump /tmp/ -d')
process = Popen(command, stdout=PIPE, stderr=PIPE)
stdout, stderr = process.communicate()

Using Subprocess in easiest way!!

import subprocess
cmd = 'pip install numpy'.split() #replace with your command
subprocess.call(cmd)

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