Background

I needed to confirm a machine name.

It is easy to do so via accessing the machine and running a few system commands.

But, want to do so programmatically, as well.

Choices

Here are some of the options for getting a machine name in PowerShell.

1. Get Computer Name Using Environment Variables
2. .Net Class
   • System.Environment
   • System.Net.DNS

 

Script

Get Computer Name using Environment Variables

Outline

1. Use Powershell $env object
2. The various platforms use different variable names
   • MS Windows
     • Computer
   • Linux
     • HOSTNAME

Code

function getMachineNameUsingEnvironmentVariable
{
    <#
       Get computer name using environment variables
    #>
    
    [string] $computer="";
    [string] $hostname="";
    

    #Get computer name from environment variable
    $computer = $env:COMPUTERNAME;
    $hostname = $env:HOSTNAME;


    $header = "Environment Variable"
    Write-Host $header

    #Get length of header
    $len = $header.length;

    <#
        Get header separator
        Create new string using character and length
    #>
    $headerSeparator = new-object System.String( $CHAR_SEPARATOR, $len );;

    Write-Host $headerSeparator;

    <#
        Display Environment Variable - COMPUTER
    #>
    $log = [string]::Format($FORMAT_ENTRY, "`$env:COMPUTER", $computer);

    Write-Host $log;

    <#
        Display Environment Variable - HOSTNAME
    #>
    $log = [string]::Format($FORMAT_ENTRY, "`$env:HOSTNAME", $hostname);

    Write-Host $log

    Write-Host ""
    Write-Host ""
 
}

 

Get Computer Name using .Net Class System.Environment

Outline

1. Uses Microsoft.Net System.Environment class
2. System.Environment Properties
   • MachineName

Code

function getMachineNameUsingEnvironmentClass
{
    
    [string] $machineName = "";
    
    <#
       Get machine name from System.Environment class
    #>
    #Get computer name from environment variable
    $machineName = [System.Environment]::MachineName;


    $header = "[System.Environment] Class"
    Write-Host $header

    #Get length of header
    $len = $header.length;

    <#
        Get header separator
        Create new string using character and length
    #>
    $headerSeparator = new-object System.String( $CHAR_SEPARATOR, $len );;

    Write-Host $headerSeparator;

    <#
        Display [System.Environment]::MachineName
    #>
    $log = [string]::Format($FORMAT_ENTRY, "[System.Environment]::MachineName", $machineName);

    Write-Host $log;

    Write-Host ""
    Write-Host ""

}

 

 

Get Computer Name using .Net Class System.Net.DNS

Outline

1. Uses Microsoft.Net System.Net.DNS class
2. Methods
   • [System.Net.DNS]::GetHostEntry
   • [System.Net.DNS]::GetHostByName

Code

function getIPAddressListAsString([System.Net.IPHostEntry] $ipHostEntry)
{
    
    <#
        Concatenate IPAddresses from System.Net.IPHostEntry
    #>
    [int] $index=0;
    [string] $ipAddressList ="";

    
    for($index=0; $index -lt $ipHostEntry.AddressList.Length; $index++)
    {        
            
        $ipAddress = $ipHostEntry.AddressList[$index];
            
        <#
            If this is not the first match, add a separator
        #>
        if ($index -gt 0)
        {
            $ipAddressList = $ipAddressList + $CHAR_COMMA;
        }        
        
        $ipAddressList = $ipAddressList + $ipAddress;
            
    }
    
    $ipAddressList = $ipAddressList.trim();
    
    return ($ipAddressList);

}

function getMachineNameUsingDNS
{
    
    <#
        Get MachineName from DNS
    #>
    
    [string] $hostnameToUseInDNSCalls="";
    [System.Net.IPHostEntry] $ipHostEntryUsingDNSHostEntry = $null;
    [System.Net.IPHostEntry] $ipHostEntryUsingDNSHostByName = $null;    

    Write-Host ""
    Write-Host ""

    
    [Boolean] $ipHostEntryUsingDNSHostEntryUsable = $false;

    [Boolean] $ipHostEntryUsingDNSHostByNameUsable = $false;

    [String] $hostnameFromUsingDNSHostEntry = $null;
    [string] $hostnameFromUsingDNSHostByName  = $null;

    <#
        [System.Net.DNS]::GetHostEntry
    #>
    $ipHostEntryUsingDNSHostEntry  = [System.Net.DNS]::GetHostEntry(($hostnameToUseInDNSCalls));


    <#
        [System.Net.DNS]::GetHostByName
    #>
    $ipHostEntryUsingDNSHostByName = [System.Net.DNS]::GetHostByName(($hostnameToUseInDNSCalls));


    if ( $ipHostEntryUsingDNSHostEntry -ne $null)
    {

      $hostnameFromUsingDNSHostEntry =  $ipHostEntryUsingDNSHostEntry.Hostname;
      
      $ipHostEntryUsingDNSHostEntryUsable = $true;
      
    }
    else
    {
        $ipHostEntryUsingDNSHostEntryUsable = $false; 
    }
    
    if ($ipHostEntryUsingDNSHostByName -ne $null )
    {

      $hostnameFromUsingDNSHostByName = $ipHostEntryUsingDNSHostByName.Hostname;
      
      $ipHostEntryUsingDNSHostByNameUsable = $true;

    }
    else
    {
        $ipHostEntryUsingDNSHostByNameUsable = $false; 
    }
    
    $header = "DNS"

    Write-Host $header;

    $len = $header.length;

    $headerSeparator = new-object System.String ( $CHAR_SEPARATOR, $len );

    Write-Host $headerSeparator;

    if ($ipHostEntryUsingDNSHostEntryUsable)
    {
        $log = [string]::Format($FORMAT_ENTRY, "DNS::GetHostEntry", $hostnameFromUsingDNSHostEntry  );

        Write-Host $log;
        
        Write-Host ""

    }
    
    if ( $ipHostEntryUsingDNSHostEntryUsable)
    {
        
        $ipAddressList = getIPAddressListAsString ( $ipHostEntryUsingDNSHostEntry);

        $log = [string]::Format($FORMAT_ENTRY_DETAIL, "IP Address List",  $ipAddressList);

        Write-Host $log
        
        Write-Host ""

    }
    
    if ($ipHostEntryUsingDNSHostByNameUsable)
    {
        
        $log = [string]::Format($FORMAT_ENTRY, "DNS::GetHostByName", $hostnameFromUsingDNSHostByName);

        Write-Host $log
        
        Write-Host ""

    }


    if ($ipHostEntryUsingDNSHostByNameUsable)
    {
        
        $ipAddressList = getIPAddressListAsString ( $ipHostEntryUsingDNSHostByName);

        $log = [string]::Format($FORMAT_ENTRY_DETAIL, "IP Address List",  $ipAddressList);

        Write-Host $log
        
        Write-Host ""

    }
    
    Write-Host ""
    Write-Host ""


}

 

Output

Output – Microsoft

Output – Linux

 

Source Code

GitLab

Get Machine Name

Get Machine Name
link

 

Reference

1. Microsoft
   • Docs
     • .Net
       • Docs > .NET > .NET API browser > System
         • Environment Class
           Link
       • Docs > .NET > .NET API browser > System.Net > IPHostEntry
         • IPHostEntry
           Link
         • IPHostEntry.AddressList Property
           Link
     • Powershell
       • Docs > PowerShell > Scripting
         • about_Environment_Variables
           Link
2. StackOveflow
   • Powershell: Get FQDN Hostname
     Link