Get-ADSIGlobalCatalog.ps1

function Get-ADSIGlobalCatalog
{
<#
.SYNOPSIS
    Function to retrieve the Global Catalog in the Forest

.DESCRIPTION
    Function to retrieve the Global Catalog in the Forest

.PARAMETER Credential
    Specifies the alternative credential to use. Default is the current user.

.PARAMETER ForestName
    Specifies the alternative Forest name to query. Default is the current one.

.EXAMPLE
    Get-ADSIGlobalCatalog

    Retrieve the Global Catalog in the current Forest

.EXAMPLE
    Get-ADSIGlobalCatalog -forestname 'lazywinadmin.com'

    Retrieve the Global Catalog in the forest 'lazywinadmin.com'

.NOTES
    Francois-Xavier Cat
    www.lazywinadmin.com
    @lazywinadm
    github.com/lazywinadmin/AdsiPS
#>

    [CmdletBinding()]
    [OutputType('System.DirectoryServices.ActiveDirectory.GlobalCatalog')]
    param
    (
        [Alias("RunAs")]
        [System.Management.Automation.PSCredential]
        [System.Management.Automation.Credential()]
        $Credential = [System.Management.Automation.PSCredential]::Empty,

        $ForestName = [System.DirectoryServices.ActiveDirectory.Forest]::Getcurrentforest()
    )

    PROCESS
    {
        TRY
        {
            Write-Verbose -Message '[Get-ADSIGlobalCatalog][PROCESS] Credential or FirstName specified'
            (Get-ADSIForest @PSBoundParameters).GlobalCatalogs
        }
        CATCH
        {
            $pscmdlet.ThrowTerminatingError($_)
        }
    }
}