Added support for PYTHONSTARTUP to shell command.

flask/cli.py

@@ -410,7 +410,18 @@ def shell_command():
         app.debug and ' [debug]' or '',
         app.instance_path,
     )
-    code.interact(banner=banner, local=app.make_shell_context())
+    ctx = {}
+
+    # Support the regular Python interpreter startup script if someone
+    # is using it.
+    startup = os.environ.get('PYTHONSTARTUP')
+    if startup and os.path.isfile(startup):
+        with open(startup, 'r') as f:
+            eval(compile(f.read(), startup, 'exec'), ctx)
+
+    ctx.update(app.make_shell_context())
+
+    code.interact(banner=banner, local=ctx)
 
 
 cli = FlaskGroup(help="""\