Following are excerpted from Build appliances with QEMU and OpenBSD, BSD Magazine, 2011.04.

  • Boot from an ISO image:    qemu -cdrom image.iso
  • Create new hard disk for a VM:    qemu-img create disk.bin 2G
  • Install OS into the virtual disk:    qemu -hda disk.bin -cdrom image.iso
  • Boot VM from virtual disk:    qemu disk.bin
  • Boot VM with two virtual disks:    qemu -hda first.bin -hdb second.bin
  • Start VM in bridge mode network:    qemu -net nic -net tap disk.bin
  • Simulate multiple network cards:   qemu -net nic,model=lance -net nic,model=pcnet -net nic,model=rt18139 disk.bin
  • QEMU can also be used with remote machines without X in -nographic mode. For this you have to have this in boot.conf(FreeBSD):

# cat /etc/boot.conf
set tty com0


And start QEMU with command:

qemu -nographic disk.bin