Get-GCHostsFileEntry.ps1
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<#
.SYNOPSIS Returns any hosts file entries in the form of PSCustomObjects. .DESCRIPTION Reads the contents of the %SYSTEMROOT%\System32\drivers\etc\hosts file returning the results as an item or array of PS custom objects. The returned objects have the following schema: [PSCustomObject]@{ IPAddress=[IPAddress]; HostNames=[String[]]; Comment=[String]; } Hosts file single line comments are ignored. Type 'Get-Help Get-GCHostsFileEntry -Online' for extra information. .PARAMETER HostName Filters the result by host name. Supports a single host name value or an array of host names. .PARAMETER IPAddress Filters the result by host ip address. Supports a single ip address or an array of ip addresses. .EXAMPLE The following example gets the list of IP addresses in the hosts file and stores them as strings into the $ip variable: $entries = Get-GCHostFileEntry $ip = $entries.IPAddress.IPAddressToString #> function Get-GCHostsFileEntry { [CmdletBinding(DefaultParameterSetName='ByName', HelpUri = 'https://github.com/grantcarthew/GCPowerShell')] [OutputType([PSCustomObject[]])] Param ( [Parameter(Mandatory=$false, Position=0, ValueFromPipeline=$true, ValueFromPipelineByPropertyName=$true, ParameterSetName='ByName')] [String[]] $HostName, [Parameter(Mandatory=$false, Position=0, ValueFromPipeline=$true, ValueFromPipelineByPropertyName=$true, ParameterSetName='ByIP')] [String[]] $IPAddress ) begin { Write-Verbose -Message "Function initiated: $($MyInvocation.MyCommand)" $hostsFilePath = Join-Path -Path $env:SystemRoot -ChildPath '\System32\drivers\etc\hosts' Write-Verbose -Message "Hosts file path set to: $hostsFilePath" Write-Verbose -Message "Getting content from hosts file." $lines = Get-Content -Path $hostsFilePath $entries = New-Object -TypeName System.Collections.ArrayList $lineElements = New-Object -TypeName System.Collections.ArrayList } process { if ($IPAddress) { Write-Verbose -Message "Filtering with IPAddress: $IPAddress" } if ($HostName) { Write-Verbose -Message "Filtering with HostName: $HostName" } if (-not $IPAddress -and -not $HostName) { Write-Verbose -Message "Retrieving all hosts file entries"} foreach ($line in $lines) { if ($line -notmatch '^$|^\s*$|^\s*#') { $comment = '' $content = $line if ($line -match '#') { $hashIndex = $line.IndexOf('#') $remainder = $line.Length - $hashIndex $comment = $line.Substring($hashIndex, $remainder) $content = $line.Substring(0, $hashIndex) } $lineElements.clear() $lineElements.AddRange($content.Trim() -split '\s+') if ($lineElements.Count -ge 2) { $addReturnItem = $false if (-not $HostName -and -not $IPAddress) { $addReturnItem = $true } elseif ($IPAddress -and $IPAddress.Trim() -eq $lineElements[0]) { Write-Verbose -Message "IPAddress match: $($lineElements[0])" $addReturnItem = $true } else { for ($i = 1; $i -lt $lineElements.Count; $i++) { if ($HostName -and $HostName.Trim().ToUpper() -eq $lineElements[$i].ToUpper()) { Write-Verbose -Message "HostName match: $($lineElements[$i])" $addReturnItem = $true } } } if ($addReturnItem) { $ip = $lineElements[0] $lineElements.RemoveAt(0) $entries.Add( [PSCustomObject]@{ IPAddress=[IPAddress]$ip; HostNames=[String[]]$lineElements.ToArray(); Comment=[String]$comment; } ) | Out-Null } } else { Write-Warning -Message "Invalid hosts file line: " + $line } } } } end { if ($entries.Count -eq 1) { Write-Output -InputObject $entries[0] } elseif ($entries.Count -gt 1) { Write-Output -InputObject $entries } else { Write-output -InputObject $null } Write-Verbose -Message "Total hosts entries: $($entries.Count)" Write-Verbose -Message "Function completed: $($MyInvocation.MyCommand)" } } |