python: can’t open file ‘manage.py’: [Errno 2] No such file or directory

**原因：**在A目录下执行“ python3 manage.py runserver x.x.x.x:1111”,但是manage.py不在A目录，在B目录，而B目录在A目录下面
**解决方法：**cd到B目录，执行“python3 manage.py runserver x.x.x.x:1111”