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!

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