start_cleaner_modified.py

def start_cleaner_modified():
    """
    Start ``sage-cleaner`` in a new process group.
    """
    pid = os.fork()
    if not pid:
        os.setpgid(os.getpid(), os.getpid())

        # Redirect stdin, stdout, stderr to /dev/null
        with open(os.devnull, "r+") as f:
            os.dup2(f.fileno(), 0)
            os.dup2(f.fileno(), 1)
            os.dup2(f.fileno(), 2)

        # Close all other file descriptors
        try:
            maxopenfiles = os.sysconf("SC_OPEN_MAX")
            if maxopenfiles <= 0:
                raise ValueError
        except ValueError:
            maxopenfiles = 1024
        os.closerange(3, maxopenfiles)

        os.execlp("sage-cleaner", "sage-cleaner")
    else:
        os.waitpid(pid, 0)

# Replace the original start_cleaner
sage.interfaces.cleaner.start_cleaner = start_cleaner_modified