Write Error - PowerShell

Overview

The Write-Error command in PowerShell allows you to write an error message to the console, redirect it to a variable, or log it to a file. It’s commonly used for handling exceptions, providing diagnostic information, or generating controlled errors for testing purposes.

Syntax

Write-Error [-Message] <string> [-ErrorId] <string> [-Category] <System.Management.Automation.ErrorCategory> [-Exception] <System.Exception> [-Source] <string> [-TargetObject] <object> [-Verbose] [-WarningAction] <System.Management.Automation.ActionPreference>

Options/Flags

| Option/Flag | Description | Default Value |
|—|—|—|
| -Message | The error message to write. | None |
| -ErrorId | A unique identifier for the error. | None |
| -Category | The category of the error. Valid values: Error, Warning, Information, Verbose, Debug. | Error |
| -Exception | An Exception object associated with the error. | None |
| -Source | The source of the error. | Current script name |
| -TargetObject | The target object associated with the error. | None |
| -Verbose | Displays the error message in verbose mode. | False |
| -WarningAction | Controls how warnings are handled. Valid values: Continue, Inquire, SilentlyContinue, Stop. | Continue |

Examples

Example 1: Writing a simple error message

Write-Error "An error occurred."

Example 2: Writing an error with an error ID and category

Write-Error -Message "File not found." -ErrorId "FileNotFound" -Category Error

Example 3: Writing an error to a file

Write-Error -Message "Error log" | Out-File error.log

Common Issues

  • Ambiguous error messages: Make sure error messages are clear and informative.
  • Overuse of error messages: Avoid bombarding users with excessive errors.
  • Not handling errors correctly: Use -ErrorAction or -Exception to handle errors programmatically.

Integration

  • -Exception can be used to capture and log exception details.
  • Write-Error can be combined with If and Try/Catch blocks for conditional error handling.
  • It can be used in conjunction with Tee-Object to simultaneously display and log errors.
  • Throw
  • Write-Error
  • Write-Warning
  • Get-Error