How to enable cheats for an already started solo game?

Sure, here is the translation:
-Go to %appdata%\.minecraft\saves\"tamap"
Close your game, cut your folder and place it in a folder "Serv" on your desktop. Then go to Minecraft.net and download Minecraft_Server.exe and put it in the same folder as your map (Serv) and rename your map to "world".
Launch MineServer and when the console stops printing, type "gamerule keepinventory true" to keep your stuff when you die.
Then move your map back to .minecraft and relaunch the game and it’s done!

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The Youtuber-Helper!

I have too many items, but when I talk about cheating, I'm not necessarily referring to give or gm, but to other commands inaccessible based on mods. When creating a map, there is the option to "enable cheats"; I disabled it, but I would like to be able to reactivate it.

Install Pipix, and in Pipix you will find a Mods tab, find TooManyItems for your version and you will have all the items you need!

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The Youtuber-Helper!

Yes, you just need to open your server without connecting, and instead of cutting the folder of your saves, copy it to avoid any risk.

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The Youtuber-Helper!

For what purpose? By activating cheat mode, you don't access many more commands... Otherwise, you have to convert your world for multiplayer, change the game mode and activate cheats, then switch it back to single player.

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The Youtuber-Helper!

And if there are mods installed with the map and those mods modify the landscape by adding blocks and mobs, will the server still work?

Thank you very much for your help ThePiicasso. It worked well.

As I said, I don't want to change my playstyle, I just want to be able to use the command: /gamerule keepinventory true.

Non