Write-Debug

Writes a debug message to the console.

Syntax

Write-Debug
     [-Message] <String>
     [<CommonParameters>]

Description

The Write-Debug cmdlet writes debug messages to the console from a script or command.

By default, debug messages are not displayed in the console, but you can display them by using the Debug parameter or the $DebugPreference variable.

Examples

Example 1: Understand $DebugPreference

This example writes a debug message.

Write-Debug "Cannot open file."

The default value of $DebugPreference is SilentlyContinue. Therefore, the message is not displayed in the console.

Example 2: Change the value of $DebugPreference

This example shows the effect of changing the value of the $DebugPreference variable. First, we display the current value of $DebugPreference and attempt to write a debug message. Then we change the value of $DebugPreference to Continue, which allows debug messages to be displayed.

PS> $DebugPreference
SilentlyContinue
PS> Write-Debug "Cannot open file."
PS>
PS> $DebugPreference = "Continue"
PS> Write-Debug "Cannot open file."
DEBUG: Cannot open file.

For more information about $DebugPreference, see about_Preference_Variables.

Example 3: Use the Debug parameter to override $DebugPreference

The Test-Debug function writes the value of the $DebugPreference variable to the PowerShell host and to the Debug stream. In this example, we use the Debug parameter to override the $DebugPreference value.

function Test-Debug {
    [CmdletBinding()]
    param()
    Write-Debug ('$DebugPreference is ' + $DebugPreference)
    Write-Host ('$DebugPreference is ' + $DebugPreference)
}

PS> Test-Debug
$DebugPreference is SilentlyContinue

PS> Test-Debug -Debug
DEBUG: $DebugPreference is Continue
$DebugPreference is Continue
PS> $DebugPreference
SilentlyContinue

Notice that the value of $DebugPreference changes when you use the Debug parameter. This change only affects the scope of the function. The value is not affected outside the function.

For more information about the Debug common parameter, see about_CommonParameters.

Parameters

-Message

Specifies the debug message to send to the console.

Type:String
Aliases:Msg
Position:0
Default value:None
Accept pipeline input:True (ByValue)
Accept wildcard characters:False

Inputs

System.String

You can pipe a string that contains a debug message to Write-Debug.

Outputs

None

Write-Debug only writes to the debug stream. It does not return any output.