Log cleanup automation in PowerShell - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this PowerShell log cleanup script?

This script deletes log files older than 7 days in the folder C:\Logs. What output will it produce if there are 3 files older than 7 days named log1.txt, log2.txt, and log3.txt?

PowerShell

Get-ChildItem -Path 'C:\Logs' -Filter '*.txt' | Where-Object { $_.LastWriteTime -lt (Get-Date).AddDays(-7) } | Remove-Item -Verbose

A Error: Remove-Item : Access to the path 'C:\Logs\log1.txt' is denied.

B

VERBOSE: Removing item C:\Logs\log1.txt
VERBOSE: Removing item C:\Logs\log2.txt
VERBOSE: Removing item C:\Logs\log3.txt

C No output

D

VERBOSE: Removing item C:\Logs\log1.txt
VERBOSE: Removing item C:\Logs\log2.txt

💡 Hint

The -Verbose flag shows which files are being deleted.

The script filters files older than 7 days and deletes them with verbose output. Since 3 files match, all 3 are removed with verbose messages.

📝 Syntax

intermediate

Which option correctly filters log files older than 30 days?

Choose the PowerShell command that correctly lists all .log files in D:\Logs older than 30 days.

A Get-ChildItem -Path 'D:\Logs' -Filter '*.log' | Where-Object { $_.CreationTime -lt (Get-Date).AddDays(30) }

B Get-ChildItem -Path 'D:\Logs' -Filter '*.log' | Where-Object { $_.LastWriteTime -gt (Get-Date).AddDays(-30) }

C Get-ChildItem -Path 'D:\Logs' -Filter '*.log' | Where-Object { $_.LastWriteTime -lt (Get-Date).AddDays(-30) }

D Get-ChildItem -Path 'D:\Logs' -Filter '*.log' | Where-Object { $_.LastWriteTime -lt (Get-Date).AddDays(30) }

💡 Hint

We want files older than 30 days, so compare LastWriteTime with a date 30 days ago.

Option C correctly filters files with LastWriteTime less than the date 30 days ago, meaning older than 30 days.

🔧 Debug

advanced

Why does this log cleanup script fail with an error?

The script below is intended to delete .log files older than 10 days but throws an error. What is the cause? Get-ChildItem -Path 'E:\Logs' -Filter '*.log' | Where-Object { $_.LastWriteTime -lt Get-Date.AddDays(-10) } | Remove-Item

PowerShell

Get-ChildItem -Path 'E:\Logs' -Filter '*.log' | Where-Object { $_.LastWriteTime -lt Get-Date.AddDays(-10) } | Remove-Item

A Get-Date.AddDays(-10) is incorrect syntax; Get-Date is a command and needs parentheses: (Get-Date).AddDays(-10)

B Where-Object cannot compare dates using -lt operator

C The filter '*.log' should be '*.txt' to match log files

D Remove-Item requires -Force to delete files older than 10 days

💡 Hint

Check how Get-Date and its methods are called in PowerShell.

Get-Date is a command that returns a DateTime object. To call AddDays, you must wrap Get-Date in parentheses.

🚀 Application

advanced

How to schedule a daily log cleanup task using PowerShell script?

You want to automate deleting .log files older than 14 days from C:\AppLogs every day at 2 AM. Which PowerShell command creates a scheduled task to run the cleanup script daily at 2 AM?

A $action = New-ScheduledTaskAction -Execute 'PowerShell.exe' -Argument '-File C:\Scripts\CleanupLogs.ps1'; $trigger = New-ScheduledTaskTrigger -Daily -At 2am; Register-ScheduledTask -TaskName 'DailyLogCleanup' -Action $action -Trigger $trigger

B New-ScheduledTask -TaskName 'DailyLogCleanup' -ScriptPath 'C:\Scripts\CleanupLogs.ps1' -Daily -At 2am

C schtasks /create /tn DailyLogCleanup /tr 'PowerShell.exe -File C:\Scripts\CleanupLogs.ps1' /sc hourly /st 02:00

D Register-ScheduledTask -TaskName 'DailyLogCleanup' -Script 'C:\Scripts\CleanupLogs.ps1' -Schedule Daily -Time 2am

💡 Hint

Use New-ScheduledTaskAction and New-ScheduledTaskTrigger to define the task, then Register-ScheduledTask to create it.

Option A correctly uses PowerShell cmdlets to create an action and trigger, then registers the scheduled task.

🧠 Conceptual

expert

What is the best way to ensure a PowerShell log cleanup script handles locked files gracefully?

You have a script that deletes old log files but sometimes fails because some files are locked by other processes. Which approach best handles this situation?

A Run the script as Administrator to bypass file locks

B Add -Force parameter to Remove-Item to force deletion of locked files

C Use Start-Sleep to wait 10 seconds before deleting files to avoid locks

D Use Try-Catch blocks around Remove-Item to catch errors and log locked files without stopping the script

💡 Hint

Think about error handling to keep the script running even if some files cannot be deleted.

Try-Catch lets the script continue running and handle locked files by logging or skipping them, which is safer and more reliable.

Practice

1. What is the main purpose of automating log cleanup using PowerShell scripts?

easy

A. To delete old log files and free up disk space

B. To create new log files automatically

C. To rename log files for better organization

D. To compress log files for faster access

Solution

1. Step 1: Understand log cleanup goal

   The goal is to remove old log files that are no longer needed to save disk space.

2. Step 2: Identify automation benefit

   Automating this process ensures logs are cleaned regularly without manual effort.

3. Final Answer:

   To delete old log files and free up disk space -> Option A

4. Quick Check:

   Log cleanup = delete old logs [OK]

Hint: Log cleanup means removing old logs to save space [OK]

Common Mistakes:

• Confusing cleanup with creating or renaming logs
• Thinking cleanup compresses files instead of deleting
• Assuming automation creates logs automatically

2. Which PowerShell command correctly lists log files older than 30 days in the folder C:\Logs?

easy

A. Get-ChildItem -Path 'C:\Logs' -Filter '*.log' | Where-Object { $_.LastWriteTime -gt (Get-Date).AddDays(30) }

B. Get-ChildItem -Path 'C:\Logs' -Filter '*.log' | Where-Object { $_.CreationTime -gt (Get-Date).AddDays(-30) }

C. Get-ChildItem -Path 'C:\Logs' -Filter '*.log' | Where-Object { $_.LastWriteTime -lt (Get-Date).AddDays(-30) }

D. Get-ChildItem -Path 'C:\Logs' -Filter '*.log' | Where-Object { $_.CreationTime -lt (Get-Date).AddDays(30) }

Solution

1. Step 1: Identify correct date filter

   We want files older than 30 days, so LastWriteTime should be less than (Get-Date).AddDays(-30).

2. Step 2: Check command syntax

   Get-ChildItem -Path 'C:\Logs' -Filter '*.log' | Where-Object { $_.LastWriteTime -lt (Get-Date).AddDays(-30) } uses LastWriteTime -lt (less than) 30 days ago, correctly filtering old files.

3. Final Answer:

   Get-ChildItem -Path 'C:\Logs' -Filter '*.log' | Where-Object { $_.LastWriteTime -lt (Get-Date).AddDays(-30) } -> Option C

4. Quick Check:

   Older than 30 days = LastWriteTime -lt (Get-Date).AddDays(-30) [OK]

Hint: Use -lt (less than) with AddDays(-30) for files older than 30 days [OK]

Common Mistakes:

• Using -gt instead of -lt for older files
• Filtering by CreationTime instead of LastWriteTime
• Using AddDays(30) instead of AddDays(-30)

3. What will be the output of this PowerShell script?

Get-ChildItem -Path 'C:\Logs' -Filter '*.log' | Where-Object { $_.LastWriteTime -lt (Get-Date).AddDays(-7) } | Remove-Item -WhatIf

medium

A. Throws an error because Remove-Item cannot be piped

B. Lists all .log files older than 7 days and deletes them

C. Deletes all .log files regardless of age

D. Shows which .log files older than 7 days would be deleted without deleting

Solution

1. Step 1: Understand the pipeline

   The script finds .log files older than 7 days using Get-ChildItem and Where-Object.

2. Step 2: Analyze Remove-Item with -WhatIf

   -WhatIf shows what would happen without deleting files, so no files are removed.

3. Final Answer:

   Shows which .log files older than 7 days would be deleted without deleting -> Option D

4. Quick Check:

   -WhatIf shows actions without executing [OK]

Hint: Remove-Item -WhatIf previews deletion without removing files [OK]

Common Mistakes:

• Thinking files are deleted with -WhatIf
• Assuming Remove-Item cannot be piped
• Confusing filter for files newer than 7 days

4. Identify the error in this PowerShell script intended to delete log files older than 15 days:

Get-ChildItem -Path 'C:\Logs' -Filter '*.log' | Where-Object { $_.LastWriteTime -gt (Get-Date).AddDays(-15) } | Remove-Item

medium

A. The filter uses -gt instead of -lt, so it deletes newer files

B. Remove-Item cannot be used in a pipeline

C. Get-ChildItem does not support -Filter parameter

D. The script is missing the -Recurse flag

Solution

1. Step 1: Check the date comparison operator

   -gt means greater than, so it selects files newer than 15 days, opposite of intended.

2. Step 2: Confirm correct operator for old files

   To delete files older than 15 days, use -lt (less than) with AddDays(-15).

3. Final Answer:

   The filter uses -gt instead of -lt, so it deletes newer files -> Option A

4. Quick Check:

   Older files need -lt, not -gt [OK]

Hint: Use -lt for files older than a date, not -gt [OK]

Common Mistakes:

• Using -gt instead of -lt for filtering old files
• Thinking Remove-Item can't be piped
• Assuming -Filter is unsupported by Get-ChildItem

5. You want to automate deleting log files older than 10 days from C:\Logs and log the deleted filenames to deleted_logs.txt. Which script correctly does this?

hard

A. Get-ChildItem -Path 'C:\Logs' -Filter '*.log' | Where-Object { $_.LastWriteTime -gt (Get-Date).AddDays(-10) } | Remove-Item; Out-File -FilePath 'deleted_logs.txt' -InputObject 'Deleted logs' -Append

B. Get-ChildItem -Path 'C:\Logs' -Filter '*.log' | Where-Object { $_.LastWriteTime -lt (Get-Date).AddDays(-10) } | ForEach-Object { Remove-Item $_.FullName; $_.FullName | Out-File -FilePath 'deleted_logs.txt' -Append }

C. Remove-Item -Path 'C:\Logs\*.log' -Recurse -Force; Get-ChildItem 'deleted_logs.txt' | Out-File -FilePath 'deleted_logs.txt' -Append

D. Get-ChildItem -Path 'C:\Logs' -Filter '*.log' | Remove-Item; Add-Content -Path 'deleted_logs.txt' -Value 'Logs deleted'

Solution

1. Step 1: Filter files older than 10 days

   Use Where-Object with LastWriteTime -lt (Get-Date).AddDays(-10) to select old logs.

2. Step 2: Remove files and log names

   ForEach-Object removes each file and appends its name to deleted_logs.txt using Out-File -Append.

3. Final Answer:

   Get-ChildItem -Path 'C:\Logs' -Filter '*.log' | Where-Object { $_.LastWriteTime -lt (Get-Date).AddDays(-10) } | ForEach-Object { Remove-Item $_.FullName; $_.FullName | Out-File -FilePath 'deleted_logs.txt' -Append } -> Option B

4. Quick Check:

   Filter old files + remove + log names = Get-ChildItem -Path 'C:\Logs' -Filter '*.log' | Where-Object { $_.LastWriteTime -lt (Get-Date).AddDays(-10) } | ForEach-Object { Remove-Item $_.FullName; $_.FullName | Out-File -FilePath 'deleted_logs.txt' -Append } [OK]

Hint: Use ForEach-Object to remove and log each file name [OK]

Common Mistakes:

• Filtering with -gt instead of -lt
• Logging only a fixed string, not filenames
• Deleting files without logging
• Using Remove-Item without filtering