How do I disable the daylight cycle?

I want to make a map with permanent night. I've tried gamerule dodaylightcycle false and gamerule doDayLightCycle false but neither option works. How do I disable the daylight cycle and set the map to permanent night?

1 Answer

You almost had it right: The "L" in "Daylight" is not capitalized:

/gamerule doDaylightCycle false

For the future you can better enter /gamerule do and see what autocomplete gives you.