+Each command obeys a common set of options. The general form is:
+
+virt-I<program> [-options] [domains...]
+
+where I<domains> is a list of guest names to act on. If no domains
+are specified then we act on all active domains by default.
+
+A I<domain> may be specified either by its name or by its ID. Use
+I<virsh list> to get a list of active domain names and IDs.
+
+The virt-mem tools do not work on domains which are not active
+(running or paused). eg. They do not work on shut down domains.
+