With commands you can do /time set 14000 which makes it early night or something like 18000 for late night or anything in between. That's really the only way.
/time set day
ex. /time set (time) ex. /time set day or /time set night
The command is: /time set day or /time set night. You can also use numbers (ex. /time set 15000, /time set 0, /time set 10000, etc.).
to change from day to night in minecraft without mods you have to wait until the sun goes down. to get from night to day you can right click a bed to sleep.
It is /time set [time] Replace [time] with: 0 for Day 14000 for Night
As of 1.3, commands were introduced to single-player. So, only if you have cheats enabled, issue the command: /time set night or /time set
open the chat and type /time set <number>. For example, /time set 0 would make it morning, and /time set 14000 would be night.
There is no way to command the daylight to come at night. You can, however, craft a bed and sleep in it. This will make it daylight in a few seconds.
Click t on your keyboard and write /time set night
/time set 0
If you mean Minecraft Classic, this is not possible. Minecraft classic is only meant for building, not survival. If you want to have survival, you'd have to buy the full version. To change day to night in Minecraft premium (full), as of 1.3 the command prompt was added to single-player so issue the command /time set night.
Night time is seven minutes long