Here's the basic script from a batch file. I'm trying to do something similar to this, but on Linux that would tell Minecraft(Java) that the home folder was located somewhere else (like a flash drive). If it's even possible?
set APPDATA=%CD%\ start %CD%\minecraft.exe
I have a .zip file with all the files you would extract to a root of the drive. I've wrapped up the .bat file into the .exe.