How to install Single Player Commands

I've seen confusing instructions for Single Player Commands in Minecraft. How do I install it?

Currently Single-Player Commands is not available for Minecraft 1.8

Edit: SPC for 1.8 is now out!

However, once it does become available, this is how you install it:

1. Download the .ZIP file
2. Extract it to some directory.
3. Go to the directory you just created.
4. Go to the Run box (WinKey + R)
5. Type in : %appdata%/.minecraft/bin
6. Look for a file called minecraft.jar
7. Rename that file to minecraft.jar.zip
8. Unzip it
9. Drag all files ending with .CLASS into the minecraft.jar FOLDER (all the files except WorldEdit.jar)
10. Go back to the folder that has the minecraft.jar in it
11. Drag the WorldEdit.jar file into this directory.
12. Go back into the minecraft.jar FOLDER
13. Delete the META-INF folder.

14. You're done! However, Minecraft may not launch. If this happens, launch Minecraft from the Run box like this:

    java -Xms512m -Xmx1024m -cp "%APPDATA%\.minecraft\bin\*" -Djava.library.path="%APPDATA%\.minecraft\bin\natives" net.minecraft.client.Minecraft
    

Or, you could use the automated installer

NOTE: At the time of this writing, Single Player Commands (SPC) is not available for the current Minecraft version, 1.8. This will change in the future, check back at their thread to see if it's updated periodically. You must install a compatible version of SPC onto the appropriate Minecraft version, which right now means you need Minecraft 1.7.3

Single Player Commands can be installed with the automated installer that is available from the link on their thread. Running this file will allow you to patch your Minecraft.jar file with the SPC mod. You can back up your maps and/or binary before doing so, in case you wish to revert later.

Instructional Video:

After installing, launch Minecraft then you can use any of the listed commands by pressing T or the chat button, typing them in and hitting enter.