QEMU is a quite complex application, with lots of command line parameters and many different ways to configure its devices, backends and other options. Many of the interfaces are legacy that are kept to stay compatible with older versions of QEMU, other interfaces are well architected and the preferred way of configuration nowadays. This talk will give you a good survey of how to use QEMU directly from the command line and hopefully help to understand how and why some parameters have to be specified in a certain way. If you are new to running QEMU directly from the command line, or if you ever asked yourself a question like "what is the difference between '-net' and '-netdev'", then this is definitely the right talk for you!