源代码文件
1.test_main.py
#!/usr/bin/python
if __name__ == "__main__":
print "I am the main program."
else:
print "Someone is importing me."
运行结果:

2.echo.py
#!/usr/bin/python
import test_main
print "echo: __name__ is", __name__
运行结果:

3.import_echo.py
#!/usr/bin/python
import echo
print "After import, __name__ is", __name__, "and echo.__name__ is", echo.__name__
运行结果:

