Difference between subprocess Popen and os system

Question

What is the difference between subprocess Popen   and os system

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os system is equivalent to Unix system command  while subprocess was a helper module created to provide many of the facilities provided by the Popen commands with an easier and controllable interface  Those were designed similar to the Unix Popen command   system   executes a command specified in command by calling  bin sh -c command  and returns after the command has been completed  Whereas   The popen   function opens a process by creating a pipe  forking  and invoking the shell   If you are thinking which one to use  then use subprocess definitely because you have all the facilities for execution  plus additional control over the process

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When running python  cpython  on windows the  lt built-in function system gt  os system will execute under the curtains  wsystem while if you re using a non-windows os  it ll use system   On contrary  Popen should use CreateProcess on windows and  posixsubprocess fork exec in posix-based operating-systems   That said  an important piece of advice comes from os system docs  which says      The subprocess module provides more powerful facilities for spawning   new processes and retrieving their results  using that module is   preferable to using this function  See the Replacing Older Functions   with the subprocess Module section in the subprocess documentation for   some helpful recipes

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subprocess Popen   is strict super-set of os system

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If you check out the subprocess section of the Python docs  you ll notice there is an example of how to replace os system   with subprocess Popen     sts   os system  mycmd      myarg        does the same thing as     sts   Popen  mycmd      myarg   shell True  wait     The  improved  code looks more complicated  but it s better because once you know subprocess Popen    you don t need anything else  subprocess Popen   replaces several other tools  os system   is just one of those  that were scattered throughout three other Python modules   If it helps  think of subprocess Popen   as a very flexible os system

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Subprocess is based on popen2  and as such has a number of advantages - there s a full list in the PEP here  but some are    using pipe in the shell better newline support better handling of exceptions

[python] Difference between subprocess.Popen and os.system

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