Trace-Command

Trace-Command
    [-Name] <String[]>
    [-Expression] <ScriptBlock>
    [[-Option] <PSTraceSourceOptions>]
    [-InputObject <PSObject>]
    [-ListenerOption <TraceOptions>]
    [-FilePath <String>]
    [-Force]
    [-Debugger]
    [-PSHost]
    [<CommonParameters>]

Trace-Command
    [-Name] <String[]>
    [-Command] <String>
    [[-Option] <PSTraceSourceOptions>]
    [-InputObject <PSObject>]
    [-ArgumentList <Object[]>]
    [-ListenerOption <TraceOptions>]
    [-FilePath <String>]
    [-Force]
    [-Debugger]
    [-PSHost]
    [<CommonParameters>]

The Trace-Command cmdlet configures and starts a trace of the specified expression or command. It works like Set-TraceSource, except that it applies only to the specified command.

PS C:\> Trace-Command -Name metadata,parameterbinding,cmdlet -Expression {Get-Process Notepad} -PSHost

This command starts a trace of metadata processing, parameter binding, and cmdlet creation and destruction of the Get-Process Notepad expression. It uses the Name parameter to specify the trace sources, the Expression parameter to specify the command, and the PSHost parameter to send the output to the console. Because it does not specify any tracing options or listener options, the command uses the defaults--All for the tracing options, and None for the listener options.

PS C:\> $A = "i*"
PS C:\> Trace-Command ParameterBinding {Get-Alias $Input} -PSHost -InputObject $A

These commands trace the actions of the ParameterBinding operations of Windows PowerShell while it processes a Get-Alias expression that takes input from the pipeline.

In Trace-Command, the InputObject parameter passes an object to the expression that is being processed during the trace.

The first command stores the string "i*" in the $A variable. The second command uses the Trace-Command cmdlet with the ParameterBinding trace source. The PSHost parameter sends the output to the console.

The expression being processed is Get-Alias $Input, where the $Input variable is associated with the InputObject parameter. The InputObject parameter passes the variable $A to the expression. In effect, the command being processed during the trace is Get-Alias -InputObject $A" or "$A | Get-Alias.

This cmdlet supports the common parameters: -Debug, -ErrorAction, -ErrorVariable, -InformationAction, -InformationVariable, -OutBuffer, -OutVariable, -PipelineVariable, -ProgressAction, -Verbose, -WarningAction, and -WarningVariable. For more information, see about_CommonParameters.

You can pipe objects that represent input to the expression to Trace-Command.

Returns the command trace in the debug stream.

• Tracing is a method that developers use to debug and refine programs. When tracing, the program generates detailed messages about each step in its internal processing.

• The Windows PowerShell tracing cmdlets are designed to help Windows PowerShell developers, but they are available to all users. They let you monitor nearly every aspect of the functionality of the shell.

• To find the Windows PowerShell components that are enabled for tracing, type Get-Help Get-TraceSource.

  A trace source is the part of each Windows PowerShell component that manages tracing and generates trace messages for the component. To trace a component, you identify its trace source.

  A trace listener receives the output of the trace and displays it to the user. You can elect to send the trace data to a user-mode or kernel-mode debugger, to the host or console, to a file, or to a custom listener derived from the System.Diagnostics.TraceListener class.

• When you use the commandSet parameter set, Windows PowerShell processes the command just as it would be processed in a pipeline. For example, command discovery is not repeated for each incoming object.

• The names of the Name, Expression, Option, and Command parameters are optional. If you omit the parameter names, the unnamed parameter values must appear in this order: Name, Expression, Option or Name, Command, Option. If you include the parameter names, the parameters can appear in any order.