liveBook · Manning

Cmdlet-based filtering

As explained in Practical Automation with PowerShell: Effective scripting from the console to the cloud

Cmdlet-based filtering is the technique of restricting command results through a cmdlet's filtering parameters before output is produced.

Cmdlet-based filtering restricts results through a cmdlet's own parameters before downstream processing. In a file watcher, this keeps the watcher focused on finding only the files it needs and leaves heavier actions to a separate action script. section 3.3.1

Filter XML files with Get-ChildItem

Get-ChildItem -Filter '*.xml' limits the returned items to XML files. This avoids returning every item and filtering afterward with Where-Object, reducing watcher runtime. section 3.3.1

Apply the technique alongside scoped watcher design:

  • Use cmdlet parameters instead of Where-Object whenever the cmdlet provides an equivalent filter. section 3.3.1
  • Scope commands to the specific folders or organizational units required rather than relying on broad recursive searches. section 3.3.1

How Practical Automation with PowerShell: Effective scripting from the console to the cloud covers it

How deep it goes
Compares cmdlet parameters with Where-Object and explains their runtime effect, without developing a broader filtering framework.
Examples
Uses Get-ChildItem -Filter '*.xml' and scoped folder or Active Directory OU monitoring as operational examples.
What you can do after
Apply it through Get-ChildItem parameters to reduce returned data and watcher processing time.
How it connects
Connects Get-ChildItem filtering with Where-Object, file watcher automation, action scripts, and recursion avoidance.
Cover of Practical Automation with PowerShell: Effective scripting from the console to the cloud
liveBookmanning.com
Read Practical Automation with PowerShell: Effective scripting from the console to the cloud on liveBook Get the book at manning.com

Related concepts

This explainer was generated by Manning's knowledge graph from the text of Practical Automation with PowerShell: Effective scripting from the console to the cloud. The section links point to the parts of the book it draws on.