Is there any command which controls the display time at start of the game : When i build the game can i do anything in my code which makes it run immediately? I mean is there any command to control the splash screen type duration ?
If you are talking about the Unity splash screen, there is no way to disable it with the free version of Unity.
You can take a look in the Player Settings (Ctrl + Shift + B, then bottom left), under Splash Image.
With a Pro license you can disable the splash screen , or replace it with your own.
I hope that helps!
As of now, you can set the duration of minimum 2 seconds to maximum of 10 seconds.
Please find more details here : https://docs.unity3d.com/Manual/class-PlayerSettingsSplashScreen.html
Your code can be executed only in a scene (unless you can modify unity engine). Loading time will be different on different devices. Make your first scene lightweight.