Linux Find Out If CPU Support Intel VT/AMD-V Virtualization

Originally published at: https://www.cyberciti.biz/faq/linux-xen-vmware-kvm-intel-vt-amd-v-support/

How do I find out if my system support Intel - VT / AMD -V hardware virtualization extensions for host CPU using the command line options? How do I check if my Linux hardware from HP/IBM/Dell supports virtualization?