Error logging patterns in PowerShell - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

PowerShell Error Logging Output

What is the output of this PowerShell script when the command fails?

$ErrorActionPreference = 'Stop'
try {
  Get-Item 'C:\nonexistentfile.txt'
} catch {
  Write-Output "Error caught: $_"
}

PowerShell

$ErrorActionPreference = 'Stop'
try {
  Get-Item 'C:\nonexistentfile.txt'
} catch {
  Write-Output "Error caught: $_"
}

A Error caught: Cannot find path 'C:\nonexistentfile.txt' because it does not exist.

B Get-Item : Cannot find path 'C:\nonexistentfile.txt' because it does not exist.

C No output, script runs silently.

D Error caught: The term 'Get-Item' is not recognized as the name of a cmdlet.

💡 Hint

Look at how the try-catch block handles errors with Write-Output.

The script sets error action to stop, so Get-Item throws a terminating error. The catch block captures it and outputs the error message with Write-Output, showing the error text.

✅ Best Practice

intermediate

Best Practice for Logging Errors in PowerShell

Which option is the best practice for logging errors in a PowerShell script to a file with timestamps?

A Use Write-Error with Out-File to append errors: Write-Error $_ | Out-File errors.log -Append

B Use Write-Output inside catch block without timestamps: Write-Output $_

C Use Write-Host to display errors and redirect output to a file: Write-Host $_ > errors.log

D Use try-catch and inside catch use Add-Content with timestamp: Add-Content errors.log "$(Get-Date): $_"

💡 Hint

Consider how to add timestamps and append to a file safely.

Using try-catch with Add-Content and Get-Date adds timestamps and appends errors to a log file, which is a good logging practice.

❓ Troubleshoot

advanced

Troubleshooting Missing Error Logs

A PowerShell script uses this code to log errors:

try {
  Remove-Item 'C:\temp\file.txt'
} catch {
  $_ | Out-File 'error.log'
}

Why might the error.log file be empty after a failure?

PowerShell

try {
  Remove-Item 'C:\temp\file.txt'
} catch {
  $_ | Out-File 'error.log'
}

A The script lacks permissions to write to error.log, so file stays empty.

B Remove-Item does not throw an error if the file is missing, so catch never runs.

C Out-File overwrites the file but $_ is an error object, not a string, so nothing is written.

D The error variable $_ is empty because errors are non-terminating by default.

💡 Hint

Consider whether the error from Remove-Item is terminating or non-terminating.

By default, Remove-Item produces a non-terminating error when the specified file does not exist. Non-terminating errors do not trigger the catch block. Therefore, Out-File is never called, and error.log remains empty.

🔀 Workflow

advanced

PowerShell Error Logging Workflow

Which sequence correctly describes a workflow to log errors with timestamps and continue script execution?

A 1,2,3,4

B 2,1,3,4

C 1,3,2,4

D 2,3,1,4

💡 Hint

Think about setting error preference before running commands.

First set error preference to 'Stop' so errors become terminating and are caught. Then run commands in try. Catch logs errors. Then script continues.

🧠 Conceptual

expert

Understanding PowerShell Error Variable Behavior

In PowerShell, what is the difference between using $_ and $Error[0] inside a catch block for error logging?

A $_ is only available outside catch blocks; $Error[0] is only available inside catch blocks.

B $_ and $Error[0] always contain the exact same error object inside catch blocks.

C $_ contains the current error object in catch; $Error[0] is the most recent error in the global error array, which may differ.

D $_ is a string of the error message; $Error[0] is the full error object with details.

💡 Hint

Consider the scope and timing of these variables.

Inside a catch block, $_ contains the current error object, while $Error[0] is the most recent error in the global error array, which may differ if other errors occurred.