Cisco switchport mode trunk is missing a command

As tested on a physical switch, when setting an interface on trunk mode, we need to call: switchport trunk encapsulation dot1q

co-dr2.staging(config-if)#switchport mode trunk
Command rejected: An interface whose trunk encapsulation is "Auto" can not be configured to "trunk" mode.
co-dr2.staging(config-if)#switchport trunk encapsulation dot1q
co-dr2.staging(config-if)#switchport mode trunk
co-dr2.staging(config-if)#