Lost command block! [duplicate]

I was tinkering with a new command configuration, and I placed a repeating command block underground that gives me superspeed. I forgot to take it's coordinates, and I left. I was testing range, and I found it NEVER. WEARS. OFF. I can't find it anymore, and I can't turn it off!! I'm in a superflat world, so I can't really remember the place from surroundings. And now I'm stuck with level 15 speed effect.

Is there a /testforblock command that will look in a large radius, not just one block?

Solution 1:

Go download NBTExplorer.

Open it. Click on the world name you want to search. (In my case BigRed)

Click search menu, click Find.

Check the Name check box and type Command in the search field and click Find.

It will find any command blocks. If it finds the wrong one, you can use Find Next menu.

Once it locates your block, you will see this:

You can see the command and the coordinates. You can actually double click the Command portion and set the command value to nothing from NBTExplorer. If you do, make sure you are not playing that world at the same time. Also remember to click File -> Save before trying to play the world.