get key unity

// KeyCode.Space : The key you press
// GetKeyDown : Is true once, when the key is pressed 
// If you want it to be true WHILE the key is pressed, try GetKey() instead
if(Input.GetKeyDown(KeyCode.Space))
{
	// Do something
}

if (Input.GetKeyDown(KeyCode.Space))
        {
            print("space key was pressed");
        }

if(Input.GetKey(KeyCode.Space))
{
	//do somthing
}

Input.GetKey(KeyCode.Space))

if (Input.GetKey("//yourkey"))