Tracing commands - Get-CommandTraceSource

Windows PowerShell provides several cmdlets to trace various low-level PowerShell components. When tracing, components generate detailed messages about each step in its internal processing. Developers use the trace data to monitor data flow, program execution, and errors. Tracing is mostly for developers but they are available to all users.

The following shows the output of Trace-Command using its first help code example (for more information about the Trace-Command cmdlet, type: Get-Help Trace-Command -Full):

Trace-Command expects two pieces of information, one or more trace sources and an expression (enclosed in braces). We can get a list of trace sources by using the Get-TraceSource cmdlet:

PS > Get-TraceSource 

Options  Name                 Listeners  Description
-------  ----                 ---------  -----------
None     SingleShell          {Default}  SingleShell
None     MshSnapinLoadUnload  {Default}  Loading and unloading mshsnapins
None     MshConsoleInfo       {Default}  MshConsoleInfo object that is constructed from...
None     PSSnapInInfo         {Default}  PSSnapInInfo
None     PSSnapInReader       {Default}  PSSnapInReader
None     RunspaceConfigura... {Default}  RunspaceConfigurationEntryCollection
(...)

However, sometimes it is not so obvious which source we need to use to trace a specific component (cmdlet). That's why I wrote the Get-CommandTraceSource function. Give it a command name (cmdlet) and Get-CommandTraceSource will get you back the command's PSTraceSource object (if implemented).

#Requires -Version 2.0 

function Get-CommandTraceSource
{
   param(
      [Parameter(Position=0, Mandatory=$true, ValueFromPipeline=$true)]
      [System.String]$Command
   )

   process
   {
      try
      {
         $c = Get-Command $Command -CommandType Cmdlet
         $c.ImplementingType.GetField("tracer","Static,NonPublic").GetValue($null)
      }
      catch
      {
         throw
      }
   }	
}



# Example
PS > Get-CommandTraceSource -Command Start-Job

Options  Name          Listeners    Description
-------  ----          ---------    -----------
None     JobCmdlets    {Default}    Job related cmdlets

Here's a one-liner that outputs all cmdlets trace sources:

PS > Get-Command -CommandType Cmdlet | Add-Member ScriptProperty TraceSource {$this.ImplementingType.GetField("tracer","Static,NonPublic").GetValue($null).Name} -PassThru | Where-Object {$_.TraceSource} | Select-Object Name,TraceSource

Name                          TraceSource
----                          -----------
Add-Computer                  AddComputer
Add-Member                    AddMember
Checkpoint-Computer           CheckpointComputer
Clear-EventLog                ClearEventLog
Compare-Object                CompareObject
ConvertFrom-StringData        ConvertFromStringData
ConvertTo-Html                ConvertToHtml
Disable-ComputerRestore       DisableComputerRestore
Enable-ComputerRestore        EnableComputerRestore
Export-Alias                  AliasCommands
Export-ModuleMember           Parser
Export-PSSession              ExportPSSessionCommand
ForEach-Object                Parser
Get-Acl                       GetAclCommand
Get-Command                   GetCommandCmdlet
Get-ComputerRestorePoint      GetComputerRestorePoint
Get-Credential                CredentialCommands
Get-EventLog                  GetEventLog
Get-Help                      GetHelpCommand
Get-HotFix                    GetHotFix
Get-PfxCertificate            CertificateCommands
Get-PSSession                 GetPSSession
Get-Random                    GetRandomCommand
Get-Unique                    GetUnique
Get-WmiObject                 TransactionCommands
Group-Object                  GroupObjectCommand
Import-Alias                  AliasCommands
Import-LocalizedData          ImportLocalizedData
Import-PSSession              ImportPSSessionCommand
Invoke-Expression             InvokeExpressionCommand
Invoke-WmiMethod              TransactionCommands
Limit-EventLog                LimitEventLog
Measure-Command               MeasureCommandCommand
Measure-Object                MeasureObject
New-EventLog                  NewEventLog
New-Object                    NewObjectCommand
New-PSSession                 NewPSSession
New-PSSessionOption           NewPSSessionOption
New-TimeSpan                  NewTimeSpanCommand
New-WebServiceProxy           StartProcess
Out-Default                   OutDefaultCommand
Out-File                      OutFileCommand
Out-GridView                  format_out_OutGridViewCommand
Out-Host                      OutHostCommand
Read-Host                     HostCmdlets
Remove-Computer               RemoveComputer
Remove-EventLog               RemoveEventLog
Remove-Module                 Parser
Remove-PSSession              RemovePSSessionCommand
Remove-WmiObject              TransactionCommands
Reset-ComputerMachinePassword ResetComputerMachinePassword
Restart-Computer              RestartComputer
Restore-Computer              RestoreComputer
Select-Object                 SelectObject
Select-String                 SelectStringCommand
Set-Acl                       SetAclCommand
Set-Date                      SetDateCommand
Set-ExecutionPolicy           ExecutionPolicyCommands
Set-PSBreakpoint              SetPSBreakpoint
Set-PSDebug                   Parser
Set-WmiInstance               TransactionCommands
Show-EventLog                 ShowEventLogCommand
Sort-Object                   SortObject
Start-Job                     JobCmdlets
Start-Process                 StartProcess
Start-Sleep                   StartSleepCommand
Start-Transcript              StartTranscriptCommand
Stop-Computer                 StopComputer
Stop-Transcript               StopTranscriptCommand
Tee-Object                    TeeObject
Test-Connection               TestConnection
Update-FormatData             UpdateFormatDataCommand
Update-TypeData               UpdateTypeDataCommand
Where-Object                  Parser
Write-Debug                   WriteDebugCommand
Write-EventLog                WriteEventLog
Write-Output                  WriteOutputCommand
Write-Progress                WriteProgressCommand
Write-Verbose                 WriteVerboseCommand
Write-Warning                 WriteWarningCommand

See Also:

Set-TraceSource