The easiest way to shutdown a Windows machine from Linux is by using Samba’s net command. The following command will send an RPC call to the Windows machine, telling it to shutdown; 

$ net rpc SHUTDOWN -C "Comment here" -f -I xxx.xxx.xxx.xxx -U username%password

If successful, we’ll be presented with the following mesage; 

Shutdown of remote machine succeeded

Change “Comment here” with whatever shutdown comment that you would like for the shutdown, and replace xxx.xxx.xxx.xxx with the IP address of the Windows machine that we are to shutdown. A valid username and password also need to be supplied as a parameter to the the -U switch.

For this command to be successful, the user we use must have shutdown privilege on the windows machine. The Windows machine also need to have RPC enabled, and no firewall is blocking port 135 as the port used by RPC. The net command itself however is only available if Samba is installed.