Filter Data in PowerShell: Where-Object Patterns

Large result sets are overwhelming. Learn to filter and see only what matters.

How It Works

Where-Object lets you write conditions like 'show only files bigger than 1MB' or 'show only .log files'. The pipe (|) sends results to Where-Object, which filters them.

This transforms overwhelming result sets into focused, useful information.

Code Examples

Find Specific File Type

# Show only .log files

Get-ChildItem | Where-Object {$_.Name -like "*.log"}



# $_.Name is the filename

# -like uses pattern matching

Find Files by Size

# Show files bigger than 1MB

Get-ChildItem -File | Where-Object {$_.Length -gt 1MB}



# Show files smaller than 100KB

Get-ChildItem -File | Where-Object {$_.Length -lt 100KB}

Find Recent Changes

# Files modified in last 7 days

Get-ChildItem | Where-Object {$_.LastWriteTime -gt (Get-Date).AddDays(-7)}



# Files older than 90 days

Get-ChildItem | Where-Object {$_.LastWriteTime -lt (Get-Date).AddDays(-90)}

Combine Multiple Conditions

# Find .log files bigger than 1MB modified in last 30 days

Get-ChildItem | Where-Object {$_.Name -like "*.log" -and $_.Length -gt 1MB -and $_.LastWriteTime -gt (Get-Date).AddDays(-30)}

Most Used Options

• 
  -eq - Equals exactly


• 
  -like - Pattern match (use *)


• 
  -gt - Greater than


• 
  -lt - Less than


• 
  -and - Both conditions true

The Trick: Power Usage

Find what's eating your disk space:

Get-ChildItem -File -Recurse | Where-Object {$_.Length -gt 100MB} | Sort-Object Length -Descending



# Shows files over 100MB, biggest first

# Great for cleanup!

Find files to delete safely:

# Find .tmp files older than 30 days

Get-ChildItem *.tmp | Where-Object {$_.LastWriteTime -lt (Get-Date).AddDays(-30)} | Remove-Item -WhatIf



# -WhatIf shows what would happen without actually deleting!

Learn It Through Practice

Stop reading and start practicing:

👉 Practice on your browser

The interactive environment lets you type these commands and see real results.

Part of PowerShell for Beginners

This is part of the PowerShell for Beginners series:

1. 
   Getting Started - Your first commands


2. 
   Command Discovery - Find what exists


3. 
   Getting Help - Understand commands


4. 
   Working with Files - Copy, move, delete


5. 
   Filtering Data - Where-Object and Select-Object


6. 
   Pipelines - Chain commands together

Related Resources

• Official PowerShell Documentation


• Microsoft Learn - PowerShell Tutorials

Summary

You now understand:

• How this command works


• The most useful options


• One powerful trick


• Where to practice hands-on

Practice these examples until they're automatic. Mastery comes from repetition.

Practice now: Head to the interactive environment and try these commands yourself. That's how PowerShell clicks for you!

What would you like to master next?