subprocess.spawnfile
subprocess.spawnfile 属性表示启动的子进程的可执行文件名。
对于 child_process.fork()，其值将等于 process.execPath。
对于 child_process.spawn()，它的值将是可执行文件的名称。
对于 child_process.exec()，它的值将是启动子进程的 shell 的名称。
The subprocess.spawnfile property indicates the executable file name of
the child process that is launched.
For child_process.fork(), its value will be equal to
process.execPath.
For child_process.spawn(), its value will be the name of
the executable file.
For child_process.exec(), its value will be the name of the shell
in which the child process is launched.