power off / get state of vm vim-cmd

from VMware's own www

Using the ESXi command-line utility vim-cmd to power off the virtual machine

1. On the ESXi console, enter Tech Support mode and log in as root. 
2. Get a list of all registered virtual machines, identified by their VMID, Display Name, and path to the .vmx configuration file, using this command:
   
   vim-cmd vmsvc/getallvms
   
   
3. To get the current state of a virtual machine
   vim-cmd vmsvc/power.getstate VMID
   
4. Power off the virtual machine using the VMID found in Step 2 and run:
   
   vim-cmd vmsvc/power.off VMID
   
   Note: If the virtual machine fails to power off, use the following command:
   vim-cmd vmsvc/power.shutdownVMID