I have two kids with different Minecraft accounts on the same Linux computer.
Previously, I made each of them an icon which ran this:
java -cp ~/minecraft/minecraft.jar net.minecraft.LauncherFrame -email@example.com -p=password servername.example.org:3000
with a separate email and password for each kid.
This does not seem to work with the new launcher, which actually has the concept of separate-user profiles, but ironically ends up being quite a bit less elegant than this. (I asked on a minecraft forum site, but only got "why would you want to do that?")
Is there a way to similarly specify the profile to launch and server to connect to on the command line of the new launcher?