functions/Set-LmhostsEntry.ps1
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Function Set-LmhostsEntry { [CmdletBinding(SupportsShouldProcess)] [OutputType("None","lmHostsEntry")] Param( [Parameter( Position = 0, Mandatory, ValueFromPipelineByPropertyName )] [Alias('CN', 'Name')] [String]$Computername, [Parameter(Mandatory, ValueFromPipelineByPropertyName)] [ValidatePattern('(\d{1,3}\.){3}\d{1,3}')] [String]$IPAddress, [Switch]$PassThru ) Begin { Write-Verbose "[$((Get-Date).TimeOfDay) BEGIN ] Starting: $($MyInvocation.MyCommand)" if (-not (Test-Path -Path $lmfile )) { Write-Verbose "[$((Get-Date).TimeOfDay) BEGIN ] Creating a new lmhosts file: $lmfile" Set-Content -Value "#lmhosts file for resolving NETBIOS names `n" -Path $lmfile -Encoding Ascii } } #begin Process { $entry = "$IPAddress $Computername" Write-Verbose "[$((Get-Date).TimeOfDay) PROCESS] Check for existing entry $entry" #There should only be one or at least we'll only process one $existing = Get-Content -Path $lmfile | Select-String $Computername | Select-Object -Last 1 if ($existing) { [String]$line = $existing.Line Write-Verbose "[$((Get-Date).TimeOfDay) PROCESS] Processing existing entry: $line" $m = $IPv4Pattern.Match($line) $OldComputername = $m.Groups['Computername'].value $oldIP = $m.Groups['IP'].value Write-Verbose "[$((Get-Date).TimeOfDay) PROCESS] Existing Computername = $oldComputername" Write-Verbose "[$((Get-Date).TimeOfDay) PROCESS] Existing IPAddress = $oldIP" if (($oldIP -eq $IPAddress) -and ($OldComputername -eq $Computername)) { Write-Warning 'The Computername and IP address matches the current entry. No changes needed.' #exit Return } else { #modify the line $Replace = $True } } #if existing #create a backup copy of the file Write-Verbose "[$((Get-Date).TimeOfDay) PROCESS] Creating a backup file copy" Copy-Item -Path $lmfile -Destination $lmbackup #insert the line if ($Replace) { $content = Get-Content -Path $lmfile Write-Verbose "[$((Get-Date).TimeOfDay) PROCESS] Replacing $oldIP with $Ipaddress" ($content -replace $line, $entry) | Out-File -FilePath $lmfile -Encoding ascii } else { #insert at the end Write-Verbose "[$((Get-Date).TimeOfDay) PROCESS] Appending $entry" $entry | Out-File -FilePath $lmfile -Append -Encoding ascii } If ($PassThru -AND (-Not $WhatIfPreference) ) { Get-LmhostsEntry -Computername $Computername } } #process End { Write-Verbose "[$((Get-Date).TimeOfDay) END ] Ending: $($MyInvocation.MyCommand)" } #end } |