Change windows hostname from command line

The netdom.exe command line program can be used. This is available from the Windows XP Support Tools or Server 2003 Support Tools (both on the installation CD).

Usage guidelines here

I don't know of a command to do this, but you could do it in VBScript or something similar. Somthing like:

sNewName = "put new name here" 

Set oShell = CreateObject ("WSCript.shell" ) 

sCCS = "HKLM\SYSTEM\CurrentControlSet\" 
sTcpipParamsRegPath = sCCS & "Services\Tcpip\Parameters\" 
sCompNameRegPath = sCCS & "Control\ComputerName\" 

With oShell 
.RegDelete sTcpipParamsRegPath & "Hostname" 
.RegDelete sTcpipParamsRegPath & "NV Hostname" 

.RegWrite sCompNameRegPath & "ComputerName\ComputerName", sNewName 
.RegWrite sCompNameRegPath & "ActiveComputerName\ComputerName", sNewName 
.RegWrite sTcpipParamsRegPath & "Hostname", sNewName 
.RegWrite sTcpipParamsRegPath & "NV Hostname", sNewName 
End With ' oShell 

MsgBox "Computer name changed, please reboot your computer" 

Original

The previously mentioned wmic command is the way to go, as it is installed by default in recent versions of Windows.

Here is my small improvement to generalize it, by retrieving the current name from the environment:

wmic computersystem where name="%COMPUTERNAME%" 
     call rename name="NEW-NAME"

NOTE: The command must be given in one line, but I've broken it into two to make scrolling unnecessary. As @rbeede mentions you'll have to reboot to complete the update.

cmd (command):

netdom renamecomputer %COMPUTERNAME% /Newname "NEW-NAME"

powershell (windows 2008/2012):

netdom renamecomputer "$env:COMPUTERNAME" /Newname "NEW-NAME"

after that, you need to reboot your computer.