Downloads SteamOS.zip, creates ISO, installs virtualbox 4.2 & dkms, and creates virtual machine for user with boot ISO attached and EFI enabled. Requires: Ubuntu, internet, sudo access...

SteamOS_VB.sh

#!/bin/bash -e

#Set up customizeable variables

VM='SteamOS' #the name of the vm
TRASH="/tmp" #where to dump the zip and decompressed folder
ISO="steamos-1.0-uefi-amd64.iso" #what to call the iso
PUT="/tmp" #where to put the iso
VDI=$(pwd) #where to put the virtual drive

#Install FunctionL allows noninteractive install with apt
install ()
{
        sudo apt-get update
        sudo DEBIAN_FRONTEND=noninteractive apt-get -y \
        -o DPkg::Options::=--force-confdef \
        -o DPkg::Options::=--force-confold \
        install $@
}


#DEALING WITH STEAM
if [ ! -f "$TRASH/steamos.zip" ]
	then
		wget http://repo.steampowered.com/download/SteamOSInstaller.zip -O $TRASH/steamos.zip #Download SteamOS from the Web
fi

#decompress downloaded file to a folder called steamos/
if [ ! -d "$TRASH/steamos" ]
	then
	unzip -d "$TRASH/steamos/" "$TRASH/steamos.zip" 
fi

#create a virtual DVD based on the download - intended for USB drive by Steam
if [ ! -f "$TRASH/$ISO" ]
	then
		genisoimage -o "$PUT/$ISO" -r -J "$TRASH/steamos/" 
fi

#VIRTUALBOX ENVIRONMENT

#Add source for VBox Software
sudo -s <<EOF
apt-add-repository "deb http://download.virtualbox.org/virtualbox/debian saucy contrib"
#for security - digital signature for the software
wget -q http://download.virtualbox.org/virtualbox/debian/oracle_vbox.asc -O- | apt-key add - 
EOF
#Install from Apt
install virtualbox-guest-additions-iso dkms

#VIRTUALBOX VM CREATION AND CONFIGURATION
VBoxManage createhd --filename $VM.vdi --size 40000
VBoxManage createvm --name $VM --ostype "Debian_64" --register
VBoxManage storagectl $VM --name "SATA Controller" --add sata --controller IntelAHCI
VBoxManage storageattach $VM --storagectl "SATA Controller" --port 0 --device 0 --type hdd --medium "$VDI/$VM.vdi"
VBoxManage storagectl $VM --name "IDE Controller" --add ide
VBoxManage storageattach $VM --storagectl "IDE Controller" --device 0 --port 0 --type dvddrive --medium "$TRASH/$ISO"
VBoxManage modifyvm $VM --boot1 dvd --boot2 disk
VBoxManage modifyvm $VM --memory 2048 --vram 128
VBoxManage modifyvm $VM --nic1 bridged --bridgeadapter1 eth0
VBoxManage modifyvm $VM --ioapic on
VBoxManage modifyvm $VM --cpus 2
VBoxManage modifyvm $VM --firmware efi

SteamOS VirtualBox Creator