How to join split iso files?

[Mudstone]

So I wasn't actually sending the commands to the right place before. Now that I figured out how to. I copied the command that AnyOldName3 put down and now it says "The syntax of the command is incorrect". I thought it had something to do with the fact that there is no file called "RSBE01.part2.iso" (there is only part0 and part1), so I tried removing the section of the command related to the nonexistent file. It still says "The syntax of the command is incorrect" however. Further advice would be appreciated. Also for JosJuice, I was trying to follow the guide on the wiki. Though I did mess up regarding the directory.