Write-Warning

SYNOPSIS

Writes a warning message.

SYNTAX

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

DESCRIPTION

The `Write-Warning` cmdlet writes a warning message to the 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.

EXAMPLES

Example 1: Write a warning message

Write-Warning "This is only a test warning."

Example 2: Pass a string to Write-Warning

$w = "This is only a test warning."
$w | Write-Warning

Example 3: Set the $WarningPreference variable and write a warning

PS> $WarningPreference
Continue
PS> Write-Warning "This is only a test warning."
This is only a test warning.
PS> $WarningPreference = "SilentlyContinue"
PS> Write-Warning "This is only a test warning."
PS> $WarningPreference = "Stop"
PS> Write-Warning "This is only a test warning."
WARNING: This is only a test warning.
Write-Warning: The running command stopped because the preference variable "WarningPreference" or common parameter is set to Stop: This is only a test warning.

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 (../Microsoft.Powershell.Core/About/about_Preference_Variables.md).

Example 4: Set the WarningAction parameter and write a warning

PS> 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 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 (../Microsoft.Powershell.Core/About/about_CommonParameters.md).

PARAMETERS

-Message

Specifies the warning message.

Type: System.String
Parameter Sets: (All)
Aliases: Msg

Required: True
Position: 0
Default value: None
Accept pipeline input: True (ByValue)
Accept wildcard characters: False

CommonParameters

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

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.

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 lists the valid values.