Powershell Script to Update DNS on multiple servers - powershell

Question

I have received the following script to update the DNS server on a windows server. This script works great for updating one server. I would like to have this script process a text file with a list of servers to batch update multiple servers at once. I am thinking something like:
script.ps1 -ComputerName (Get-Content c:\serverlist.txt) -OldDns 10.0.0.1 -NewDns 10.0.0.2
This fails if there are multiple servers in the 'serverlist.txt'. My question is how to incorporate a ForEach that allows for every server in the 'serverlist.txt'
[CmdletBinding()]
Param(
[Parameter(Mandatory=$True,HelpMessage="Name of the computer to update")]
[String]$ComputerName,
[Parameter(Mandatory=$True,HelpMessage="DNS server to replace")]
[String]$OldDns,
[Parameter(Mandatory=$True,HelpMessage="New DNS server setting")]
[String]$NewDns,
[switch]$TestMode
)
$niclist = Get-WmiObject -Authentication PacketIntegrity -ComputerName $ComputerName -class Win32_NetworkAdapterConfiguration | where { $_.DnsServerSearchOrder -contains $OldDns }
if ($niclist) {
foreach ($nic in $niclist) {
$dns = $nic.DnsServerSearchOrder
$dns
$index = [array]::IndexOf($dns,$OldDns)
$dns[$index] = $NewDns
$dns
$nic
if (!$TestMode) {
$nic.SetDnsServerSearchOrder($dns)
}
}
}

Answer 1

Assuming your serverlist.txt contains a list of servers where one is on each line and no headers you can just pipe the content of the file into a ForEach-Object loop. The -ComputerName will be $_ which is the current item in the pipeline.
Get-Content c:\serverlist.txt | ForEach-Object{
script.ps1 -ComputerName $_ -OldDns 10.0.0.1 -NewDns 10.0.0.2
}