Never call the latter if the process is not the lead process of a process group that’s attached to the current console session the results can be buggy in ways that break the entire console session due to bad design in the session host (i.e. If a process group is in the current console session, and only if it’s in the current console session, you can kill it via p.send_signal(signal.CTRL_BREAK_EVENT). If you also want a new console session, add the flag subprocess.CREATE_NEW_CONSOLE, but generally I don’t recommend that.

In Python, the effect of the /B option is equivalent to calling subprocess.Popen with creationflags=subprocess.CREATE_NEW_PROCESS_GROUP. The start command doesn’t wait unless /W is used, e.g. If the /B option is used, then it creates a new process group in the current session.

a complex pipeline).īy default, CMD’s internal start command executes the command line in a new console session and a new console process group that ignores Ctrl+C. On Windows it’s generally wrong because subprocess.list2cmdline() only supports argument quoting and escaping that matches WinAPI CommandLineToArgvW(), but the CMD shell uses different rules, and in general multiple rule sets may have to be supported (e.g. On POSIX using an argument list with shell=True is generally wrong because the arguments are passed as parameters to the shell. This is the args parameter of the run () function.

You imported subprocess and then called the run () function with a list of strings as the one and only argument. Generally you should use a command-line string with shell=True. CompletedProcess (args 'python', 'timer.py', '5', returncode0) With this code, you should’ve seen the animation playing right in the REPL.

Run subprocess in background python