python flask 如何修改默认端口号的方法步骤

from flask import Flask
 
app = Flask(__name__)
 
@app.route('/')
def hello():
  return 'Hello, World!' 

$ env FLASK_APP=hello.py flask run 

renjg@renjg-HP-Compaq-Pro-6380-MT:~/WorkSpace/python/django$ env FLASK_APP=index.py flask run
 * Serving Flask app "index.py"
 * Environment: production
  WARNING: Do not use the development server in a production environment.
  Use a production WSGI server instead.
 * Debug mode: off
Traceback (most recent call last):
 File "/usr/local/bin/flask", line 11, in <module>
  sys.exit(main())
 File "/usr/local/lib/python2.7/dist-packages/flask/cli.py", line 894, in main
  cli.main(args=args, prog_name=name)
 File "/usr/local/lib/python2.7/dist-packages/flask/cli.py", line 557, in main
  return super(FlaskGroup, self).main(*args, **kwargs)
 File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 717, in main
  rv = self.invoke(ctx)
 File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 1137, in invoke
  return _process_result(sub_ctx.command.invoke(sub_ctx))
 File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 956, in invoke
  return ctx.invoke(self.callback, **ctx.params)
 File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 555, in invoke
  return callback(*args, **kwargs)
 File "/usr/local/lib/python2.7/dist-packages/click/decorators.py", line 64, in new_func
  return ctx.invoke(f, obj, *args, **kwargs)
 File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 555, in invoke
  return callback(*args, **kwargs)
 File "/usr/local/lib/python2.7/dist-packages/flask/cli.py", line 771, in run_command
  threaded=with_threads, ssl_context=cert)
 File "/usr/local/lib/python2.7/dist-packages/werkzeug/serving.py", line 814, in run_simple
  inner()
 File "/usr/local/lib/python2.7/dist-packages/werkzeug/serving.py", line 774, in inner
  fd=fd)
 File "/usr/local/lib/python2.7/dist-packages/werkzeug/serving.py", line 660, in make_server
  passthrough_errors, ssl_context, fd=fd)
 File "/usr/local/lib/python2.7/dist-packages/werkzeug/serving.py", line 577, in __init__
  self.address_family), handler)
 File "/usr/lib/python2.7/SocketServer.p<span style="color:transparent">本文来源gaodai#ma#com搞*!代#%^码$网!</span>y", line 417, in __init__
  self.server_bind()
 File "/usr/lib/python2.7/BaseHTTPServer.py", line 108, in server_bind
  SocketServer.TCPServer.server_bind(self)
 File "/usr/lib/python2.7/SocketServer.py", line 431, in server_bind
  self.socket.bind(self.server_address)
 File "/usr/lib/python2.7/socket.py", line 228, in meth
  return getattr(self._sock,name)(*args)
socket.error: [Errno 98] Address already in use 

renjg@renjg-HP-Compaq-Pro-6380-MT:~/WorkSpace/python/django/flask$ grep 5000 * -nrw
docs/patterns/appdispatch.rst:28:  run_simple('localhost', 5000, application, use_reloader=True)
docs/patterns/appdispatch.rst:48:    run_simple('localhost', 5000, app,
docs/config.rst:417:   * Running on http://127.0.0.1:5000/
docs/config.rst:453:   * Running on http://127.0.0.1:5000/
docs/quickstart.rst:51:   * Running on http://127.0.0.1:5000/
docs/quickstart.rst:66:   * Running on http://127.0.0.1:5000/
docs/quickstart.rst:72:Now head over to `http://127.0.0.1:5000/ <http://127.0.0.1:5000/>`_, and you
docs/deploying/wsgi-standalone.rst:38:  $ uwsgi --http 127.0.0.1:5000 --module myproject:app
docs/deploying/wsgi-standalone.rst:55:  http_server = WSGIServer(('', 5000), app)
docs/server.rst:26:*http://localhost:5000/*.
docs/cli.rst:97:   * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
docs/cli.rst:143:   * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
docs/tutorial/static.rst:58:Go to http://127.0.0.1:5000/auth/login and the page should look like the
docs/tutorial/factory.rst:169:   * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
docs/tutorial/factory.rst:174:Visit http://127.0.0.1:5000/hello in a browser and you should see the
docs/tutorial/templates.rst:174:then go to http://127.0.0.1:5000/auth/register.
examples/javascript/README.rst:39:Open http://127.0.0.1:5000 in a browser.
examples/tutorial/README.rst:62:Open http://127.0.0.1:5000 in a browser.
<strong>flask/app.py:878:    :param port: the port of the webserver. Defaults to ``5000`` or the
flask/app.py:925:    _port = 5000
flask/cli.py:738:@click.option('--port', '-p', default=5000,</strong>
README.rst:43:   * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
tests/test_basic.py:369:    SERVER_NAME='localhost:5000',
tests/test_basic.py:377:  rv = client.get('/', 'http://localhost:5000/')
tests/test_basic.py:385:    SERVER_NAME='127.0.0.1:5000',
tests/test_basic.py:393:  rv = client.get('/', 'http://127.0.0.1:5000/')
tests/test_basic.py:1448:    SERVER_NAME='localhost.localdomain:5000'
tests/test_basic.py:1463:  rv = client.get('/', 'http://localhost.localdomain:5000')
tests/test_basic.py:1466:  rv = client.get('/', 'https://localhost.localdomain:5000')
tests/test_reqctx.py:72:    SERVER_NAME='localhost.localdomain:5000'
tests/test_reqctx.py:85:        'http://localhost.localdomain:5000/'
tests/test_reqctx.py:89:        'http://foo.localhost.localdomain:5000/'
tests/test_reqctx.py:97:      "('localhost.localdomain:5000') does not match the "