User blog comment:Henzukaya/Terraria and Blackouts/@comment-14588660-20131231165019/@comment-14588660-20140102153839

It's actually really easy.

First thing you need to do is navigate to the place where Terraria saves (in Windows it's typically in Documents/My Games/Terraria, which I'll assume is where your saves are).

Once you're in Documents/My Games (no inside the Terraria folder) create a text document (Right click > new > text document) and set it's name to something like "terraria_backup.bat". In this case the .bat is the important bit (Note:  If not already done, you'll need to go to Controll panel>folder options>view and uncheck the option: hide extensions for known file types, otherwise you'll run into trouble when you try to rename the file).

Once you have your terraria_backup.bat file, right click it and choose "edit" which should open the file in notepad. Once you're in there, just copy and paste the following as the first line:

robocopy terraria terraria_bak_%date:~4,2%%date:7,2%%date:10,4% /s

Then save it and close it. Right click the file and do a "Send to > desktop" and it'll create a shortcut you can run to do the backup.

If you want to take it a step further, you can put your Terraria executable path as the second line in the file. This will be determined by which install version you have of Terraria and what operating system you are using. The easiest way to find this is to just right click > properties on any Terraria shortcut you have and copy the target line of that window into your batch file.

If you want to save a bit of space, you can also try using  the command line version of 7z to create a compressed archive of your save folder. In practice, the save folder compresses down to about 10% of the original size.

NOTE:  If you're running windows XP, robocopy probably won't work. If that's the case you'll need to download and install the official Microsoft 2003 Server resource kit before you can run the script:  http://www.microsoft.com/en-us/download/details.aspx?id=17657  Among other things, this will install robocopy for you.