functions/Get-DbaDefaultPath.ps1

function Get-DbaDefaultPath {
<#
    .SYNOPSIS
        Gets the default SQL Server paths for data, logs and backups
     
    .DESCRIPTION
        Gets the default SQL Server paths for data, logs and backups
     
    .PARAMETER SqlInstance
        The SQL Server instance, or instances.
     
    .PARAMETER SqlCredential
        Allows you to login to servers using SQL Logins as opposed to Windows Auth/Integrated/Trusted.
     
    .PARAMETER Silent
        Use this switch to disable any kind of verbose messages
     
    .NOTES
        Tags: Config
        Website: https://dbatools.io
        Copyright: (C) Chrissy LeMaire, clemaire@gmail.com
        License: GNU GPL v3 https://opensource.org/licenses/GPL-3.0
     
    .LINK
        https://dbatools.io/Get-DbaDefaultPath
     
    .EXAMPLE
        Get-DbaDefaultPath -SqlInstance sql01\sharepoint
         
        Returns the default file paths for sql01\sharepoint
     
    .EXAMPLE
        $servers = "sql2014","sql2016", "sqlcluster\sharepoint"
        $servers | Get-DbaDefaultPath
         
        Returns the default file paths for "sql2014","sql2016" and "sqlcluster\sharepoint"
 
#>
    
    [CmdletBinding()]
    param (
        [Parameter(ValueFromPipeline = $true)]
        [Alias("ServerInstance", "SqlServer")]
        [DbaInstanceParameter[]]$SqlInstance,
        [Alias("Credential")]
        [PSCredential]
        $SqlCredential,
        [switch]$Silent
    )
    process {
        foreach ($instance in $SqlInstance) {
            Write-Message -Level Verbose -Message "Attempting to connect to $instance"
            
            try {
                $server = Connect-SqlInstance -SqlInstance $instance -SqlCredential $SqlCredential
            }
            catch {
                Stop-Function -Message "Failure" -Category ConnectionError -ErrorRecord $_ -Target $instance -Continue
            }
            
            $datapath = $server.DefaultFile
            
            if ($datapath.Length -eq 0) {
                $datapath = $server.ConnectionContext.ExecuteScalar("SELECT SERVERPROPERTY('InstanceDefaultDataPath')")
            }
            
            <# eh, this can be a failback if we can get it to work ;)
            if ($datapath -eq [System.DBNull]::Value -or $datapath.Length -eq 0) {
                $datapath = $server.ConnectionContext.ExecuteScalar("master.dbo.xp_instance_regread N'HKEY_LOCAL_MACHINE', N'Software\Microsoft\MSSQLServer\MSSQLServer', N'DefaultData'")
            }
            #>

            
            if ($datapath -eq [System.DBNull]::Value -or $datapath.Length -eq 0) {
                $datapath = Split-Path (Get-DbaDatabase -SqlInstance $server -Database model).FileGroups[0].Files[0].FileName
            }
            
            if ($datapath.Length -eq 0) {
                $datapath = $server.Information.MasterDbPath
            }
            
            $logpath = $server.DefaultLog
            
            if ($logpath.Length -eq 0) {
                $logpath = $server.ConnectionContext.ExecuteScalar("SELECT SERVERPROPERTY('InstanceDefaultLogPath')")
            }
            
            <#
            eh, this can be a failback if we can get it to work ;)
            right now, the Get-Database thing below causes enumeration which slows stuff down on systems with hundreds of dbs
            if ($logpath -eq [System.DBNull]::Value -or $logpath.Length -eq 0) {
                $logpath = $server.ConnectionContext.ExecuteScalar("master.dbo.xp_instance_regread N'HKEY_LOCAL_MACHINE', N'Software\Microsoft\MSSQLServer\MSSQLServer', N'DefaultLog'")
            }
            #>

            
            if ($logpath -eq [System.DBNull]::Value -or $logpath.Length -eq 0) {
                $logpath = Split-Path (Get-DbaDatabase -SqlInstance $server -Database model).LogFiles.FileName
            }
            
            if ($logpath.Length -eq 0) {
                $logpath = $server.Information.MasterDbLogPath
            }
            
            $datapath = $datapath.Trim().TrimEnd("\")
            $logpath = $logpath.Trim().TrimEnd("\")
            
            [pscustomobject]@{
                ComputerName = $server.NetName
                InstanceName = $server.ServiceName
                SqlInstance = $server.DomainInstanceName
                Data = $datapath
                Log = $logpath
                Backup = $server.BackupDirectory
            }
        }
    }
}