+ Each command obeys a common set of options. The general form is:
+
+ virt-*program* [-options] [domains...]
+
+ where *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 *domain* may be specified either by its name or by its ID. Use *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.
+