RunOnce to rename a Computername with a random name on reboot

Question

We are a learning center and sometimes we are not able to sysprep the machines for different reasons. When I do not sysprep the machines, I end up cloning a machine 25 times with the same computername.

I then have to go manually on each station and change the computername and restart them after.

I was wondering if I could use a batch file or powershell script that I would do before shutting down my machine (pre-cloning). Then, on next reboot (only once) the computer would randomly change the Computername and therefore save me alot of time.

I am doing this under Windows XP to Windows Server 2012R2. A unique solution working under all those OSes would be magic but I mostly do this on Server 2008+. I dont mind using a batch file for WinXP-Win7 and powershell for Windows 2008 to 2012 for example!

Thank you everyone!

Answer 1

You can generate a random name using the Get-Random cmdlet.

# Set allowed ASCII character codes to Uppercase letters (65..90), 
$charcodes = 65..90

# Convert allowed character codes to characters
$allowedChars = $charcodes | ForEach-Object { [char][byte]$_ }

$LengthOfName = 10
# Generate computer name
$pw = ($allowedChars | Get-Random -Count $LengthOfName) -join ""

You can change a computer name with the cmdlet Rename-Computer. And to set it to run once, the easiest way would be to add an entry to the registry key

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce   

that will invoke PowerShell with your script.

Answer 2

I'd like to add two ways to generate names with all allowed chars, for convenience starting with an uppercase letter and a length of 15 chars

Batch

@Echo off&SetLocal EnableExtensions EnableDelayedExpansion
Set "Chars=ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
Call :RandChar 26 Name
For /L %%A in (1,1,14) Do Call :RandChar 62 Name
Echo %Name%
Goto :Eof
:RandChar Range Var
Set /A Pnt=%Random% %% %1 & Set %2=!%2!!Chars:~%Pnt%,1!

PowerShell

$chars = [char[]]"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
[string](($chars[0..25]|Get-Random)+(($chars|Get-Random -Count 14) -join ""))