qemu-system-x86_64 -net nic,model=help outputs to stderr instead of std qemu-system-x86_64 -net nic,model=help output comes to stderr instead of std qemu-system-x86_64 -net nic,model=help -> stdout qemu-system-x86_64 -machine help -> stdout qemu-system-x86_64 -cpu help -> stdout as of https://github.com/qemu/qemu/blob/044d65525f6ac2093042ae18dbf8c1300b5c1c18/net/net.c#L831 I run qemu 2.5 on x86_64 kind regards