keyword description provides startup flags used when creating processes on windows the default value is none possible values include startf_useshowwindow and startf_usestdhandlers stderr file object representing the file to use for stderr in the child process may be file object created via open()an integer file descriptoror the special value pipewhich indicates that new pipe should be created the default value is none stdin file object representing the file to use for stdin in the child process may be set to the same values as stderr the default value is none stdout file object representing the file to use for stdout in the child process may be set to the same values as stderr the default value is none universal_newlines if truethe files representing stdinstdoutand stderr are opened in text mode with universal newline mode enabled see the open(function for full description startupinfo call(args**parmsthis function is exactly the same as popen()except that it simply executes the command and returns its status code instead (that isit does not return popen objectthis function is useful if you just want to execute command but are not concerned with capturing its output or controlling it in other ways the parameters have the same meaning as with popen(check_call(args**parmsthe same as call(except that if the exit code is non-zerothe calledprocesserror exception is raised this exception has the exit code stored in its returncode attribute the popen object returned by popen(has variety of methods and attributes that can be used for interacting with the subprocess communicate([input]communicates with the child process by sending the data supplied in input to the standard input of the process once data is sentthe method waits for the process to terminate while collecting output received on standard output and standard error returns tuple (stdoutstderrwhere stdout and stderr are strings if no data is sent to the child processinput is set to none (the defaultp kill(kills the subprocess by sending it sigkill signal on unix or calling the terminate(method on windows poll(checks to see if has terminated if sothe return code of the subprocess is returned otherwisenone is returned send_signal(signalsends signal to the subprocess signal is signal number as defined in the signal module on windowsthe only supported signal is sigterm lib fl ff