Follow these steps:
- Download the .jar version of Minecraft from the website
- Force update Minecraft on your Windows Machine and login
- Press
Ctrl+r and type %appdata% and copy your .minecraft folder
- Put it on a USB and insert the USB into your Linux Machine
- Copy the
.minecraft folder to ~/.minecraft in your Linux machine
- Login as usual and click
"Play Offline"
You will have the following Issues:
- Generally Linux doesn't have java per-installed and you will need Internet connection
- You cannot play online
You should just get a Ethernet cable and tether internet off of your windows machine. Or do as uncovery said and get cheap network cards connect them.
You can make separate work directories for the launcher and start it like this:
java -jar ~/minecraft/Minecraft.jar --workDir ~/minecraft/user1/
java -jar ~/minecraft/Minecraft.jar --workDir ~/minecraft/user2/
#etc
(For Windows users, just specify the folders as you normally would: e.g. java -jar "D:\Games\Minecraft\Minecraft.jar" --workDir "D:\Games\Minecraft\User1\")
By doing this, you will get completely separate environments for the game, so each one of them will keep its own login data (you still need to press the "Play" button), but will also have separate worlds and resource packs, and the launcher will download/update the game separately.
However, that can behavior can be changed, especially easily on Linux. You can share the singleplayer worlds, for example, if you make a symlink to one environment's saves folder in other folder(s).
There seems to be no way to connect to a server with a command line parameter, because the only command line parameters the launcher accepts right now are: work directory, proxy server, force update. (use --help to look at that)
Best Answer
No, you do not have to download another copy of minecraft. Even if you purchase a second account, you still would not download a second copy of minecraft.
If you are planning on playing single player(offline) then you can just create two separate worlds. One that is yours, one that is your sisters. You don't need two accounts to do that. You can make several worlds if you want.
If you want to play Multiplayer(online) on a server, you can still share an account. I would recommend you both play on different servers. Though, if you wanted to, you could both use the same account and play in different areas of that server.
A second account would allow you to both log into the same server and play your own games with your own game name.