Write-Warning

Writes a warning message.
Write-Warning [-Message*] <String> [<CommonParameters>]

The Write-Warning cmdlet writes a warning message to the Windows PowerShell host. The response to the warning depends on the value of the user’s $WarningPreference variable and the use of the WarningAction common parameter.

Parameters
-Message <String>

  • This value is required
  • Accepts pipeline input ByValue

Specifies the warning message.

<CommonParameters>

This cmdlet supports the common parameters: Verbose, Debug,ErrorAction, ErrorVariable, WarningAction, WarningVariable,OutBuffer, PipelineVariable, and OutVariable.

Inputs

System.String

You can pipe a string that contains the warning to Write-Warning.

Outputs

None

Write-Warning writes only to the warning stream. It does not generate any other output.

Examples
  1. Write a warning message:
    PS C:> Write-Warning "This is only a test warning."
    

    This command displays the message “WARNING: This is only a test warning.”

  2. Pass a string to Write-Warning:
    PS C:> $w = "This is only a test warning."
    PS C:> $w | Write-Warning
    

    This command shows that you can use a pipeline operator (|) to send a string to Write-Warning. You can save the string in a variable, as shown in this command, or pipe the string directly to Write-Warning.

  3. Set the $WarningPreference variable and write a warning:
    PS C:> $warningpreference
    ContinuePS C:> Write-Warning "This is only a test warning."
    This is only a test warning.PS C:> $warningpreference = "SilentlyContinue"
    PS C:> Write-Warning "This is only a test warning."
    PS C:>
    PS C:> $warningpreference = "Stop"
    PS C:> Write-Warning "This is only a test warning."
    WARNING: This is only a test message. Write-Warning : Command execution stopped because the shell variable "WarningPreference" is set to Stop. At line:1 char:14
    
            + Write-Warning 

    This example shows the effect of the value of the $WarningPreference variable on a Write-Warning command.

    The first command displays the default value of the $WarningPreference variable, which is Continue. As a result, when you write a warning, the warning message is displayed and execution continues.

    When you change the value of the $WarningPreference variable, the effect of the Write-Warning command changes again. A value of SilentlyContinue suppresses the warning. A value of Stop displays the warning and then stops execution of the command.

    For more information about the $WarningPreference variable, see about_Preference_Variables.

  4. Set the WarningAction parameter and write a warning:
    PS C:> Write-Warning "This is only a test warning." -WarningAction Inquire
    WARNING: This is only a test warning. Confirm
    Continue with this operation? [Y] Yes  [A] Yes to All  [H] Halt Command  [S] Suspend  [?] Help (default is "Y"):
    

    This example shows the effect of the WarningAction common parameter on a Write-Warning command. You can use the WarningAction common parameter with any cmdlet to determine how Windows PowerShell responds to warnings resulting from that command. The WarningAction common parameter overrides the value of the $WarningPreference only for that particular command.

    This command uses the Write-Warning cmdlet to display a warning. The WarningAction common parameter with a value of Inquire directs the system to prompt the user when the command displays a warning.

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

Additional Notes
 The default value for the $WarningPreference variable is Continue, which displays the warning and then 
 continues executing the command. To determine valid values for a preference variable such as 
 $WarningPreference, set it to a string of random characters, such as "abc". The resulting error message will 
 list the valid values.
Related Links

Write-Debug
Write-Error
Write-EventLog
Write-Host
Write-Information
Write-Output
Write-Progress
Write-Verbose