You can manage virtual machines with the vSphere Web Client or the vmware-cmd vCLI command. By using vmware-cmd you can register and unregister virtual machines, retrieve virtual machine information, manage snapshots, turn the virtual machine on and off, add and remove virtual devices, and prompt for user input.
Some virtual machine management utility applications are included in the vSphere SDK for Perl.
The VMware PowerCLI cmdlets, which you can install for use with Microsoft PowerShell, manage many aspects of virtual machines.