functions/Get-DbaTraceFlag.ps1

function Get-DbaTraceFlag {
    <#
    .SYNOPSIS
        Get global Trace Flag(s) information for each instance(s) of SQL Server.
 
    .DESCRIPTION
        Returns Trace Flags that are enabled globally on each instance(s) of SQL Server as an object.
 
    .PARAMETER SqlInstance
        The target SQL Server instance or instances. This can be a collection and receive pipeline input to allow the function to be executed against multiple SQL Server instances.
 
    .PARAMETER SqlCredential
        Login to the target instance using alternative credentials. Accepts PowerShell credentials (Get-Credential).
 
        Windows Authentication, SQL Server Authentication, Active Directory - Password, and Active Directory - Integrated are all supported.
 
        For MFA support, please use Connect-DbaInstance.
 
    .PARAMETER TraceFlag
        Use this switch to filter to a specific Trace Flag.
 
    .PARAMETER EnableException
        By default, when something goes wrong we try to catch it, interpret it and give you a friendly warning message.
        This avoids overwhelming you with "sea of red" exceptions, but is inconvenient because it basically disables advanced scripting.
        Using this switch turns this "nice by default" feature off and enables you to catch exceptions with your own try/catch.
 
    .NOTES
        Tags: TraceFlag, DBCC
        Author: Kevin Bullen (@sqlpadawan)
 
        Website: https://dbatools.io
        Copyright: (c) 2018 by dbatools, licensed under MIT
        License: MIT https://opensource.org/licenses/MIT
 
        References: https://docs.microsoft.com/en-us/sql/t-sql/database-console-commands/dbcc-traceon-trace-flags-transact-sql
 
    .LINK
        https://dbatools.io/Get-DbaTraceFlag
 
    .EXAMPLE
        PS C:\> Get-DbaTraceFlag -SqlInstance localhost
 
        Returns all Trace Flag information on the local default SQL Server instance
 
    .EXAMPLE
        PS C:\> Get-DbaTraceFlag -SqlInstance localhost, sql2016
 
        Returns all Trace Flag(s) for the local and sql2016 SQL Server instances
 
    .EXAMPLE
        PS C:\> Get-DbaTraceFlag -SqlInstance localhost -TraceFlag 4199,3205
 
        Returns Trace Flag status for TF 4199 and 3205 for the local SQL Server instance if they are enabled.
 
    #>

    [CmdletBinding()]
    param (
        [parameter(Mandatory, ValueFromPipeline)]
        [DbaInstanceParameter[]]$SqlInstance,
        [PSCredential]
        $SqlCredential,
        [int[]]$TraceFlag,
        [switch]$EnableException
    )

    process {
        foreach ($instance in $SqlInstance) {
            try {
                $server = Connect-SqlInstance -SqlInstance $instance -SqlCredential $SqlCredential
            } catch {
                Stop-Function -Message "Error occurred while establishing connection to $instance" -Category ConnectionError -ErrorRecord $_ -Target $instance -Continue
            }

            $tflags = $server.EnumActiveGlobalTraceFlags()

            if ($tFlags.Rows.Count -eq 0) {
                Write-Message -Level Output -Message "No global trace flags enabled"
                return
            }

            if ($TraceFlag) {
                $tflags = $tflags | Where-Object TraceFlag -In $TraceFlag
            }

            foreach ($tflag in $tflags) {
                [pscustomobject]@{
                    ComputerName = $server.ComputerName
                    InstanceName = $server.ServiceName
                    SqlInstance  = $server.DomainInstanceName
                    TraceFlag    = $tflag.TraceFlag
                    Global       = $tflag.Global
                    Session      = $tflag.Session
                    Status       = $tflag.Status
                } | Select-DefaultView -ExcludeProperty 'Session'
            }
        }
    }
}