This assumes you have enabled SSH connections to your ESX hypervisor. The vim-cmd vmsvc/getallvms command can be used to list each registered virtual machine.

vim-cmd vmsvc/getallvms

Something like this should be returned.

Vmid    Name                             File                                    Guest OS        Version   Annotation
33     vm1.example.com   [datastore_VMs] vm1.example.com/vm1.example.com.vmx     centos64Guest   vmx-11
37     vm2.example.com   [datastore_VMs] vm2.example.com/vm2.example.com.vmx     centos64Guest   vmx-11
54     vm3.example.com   [datastore_VMs] vm3.example.com/vm3.example.com.vmx     fedora64Guest   vmx-13

The vim-cmd vmsvc/power.getstate <id> command can be used to determine if a virtual machine is currently powered on or off.

vim-cmd vmsvc/power.getstate 33

In this example, the vm1.example.com virtual machine is currently powered off.

Retrieved runtime info
Powered off

The vim-cmd vmsvc/power.on <id> command can be used to power on a virtual machine.

vim-cmd vmsvc/power.on 33

Something like this should be returned.

Powering on VM:

To power off a virtual machine, whenever possible, the virtual machine should be powered off via the guest virtual machine. For example, if the virtual machine is a Linux system, the shutdown command should be used to power off the virtual machine. However, if for whatever reason it is not possible to shutdown the virtual machine via the guest, you would first use esxcli vm process list command to get the world ID of the virtual machine. Let's say the esxcli vm process list command returns the following. In this example, the world ID of vm1.example.com is 75260.

vm1.example.com
   World ID: 75260
   Process ID: 0
   VMX Cartel ID: 75259
   UUID: 56 4d c9 05 de c1 72 0f-6a c7 e8 23 5f d6 cd be
   Display Name: vm1.example.com
   Config File: /vmfs/volumes/57657886-7b8f67a9-b213-10bf4879952f/vm1.example.com/vm1.example.com.vmx

The esxcli vm process kill <world id> command would then be used to kill the virtual machine process.

esxcli vm process kill 75260

Then you would use the vim-cmd vmsvc/getallvms command to get the ID of the virtual machine. In this example, the ID of vm1.example.com is 33.

Vmid    Name                             File                                    Guest OS        Version   Annotation
33     vm1.example.com   [datastore_VMs] vm1.example.com/vm1.example.com.vmx     centos64Guest   vmx-11

You would then use the vim-cmd vmsvc/power.off <id> command to power off the virtual machine.

vim-cmd vmsvc/power.off 33

Something like this should be returned.

Powering off VM: