Objects

By the end of this lesson you'll be able to filter, sort, reshape, and summarise live system data using PowerShell's object pipeline — the one feature that makes it far more powerful than a traditional text-based shell.

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Part of the free Powershell course at LearnCodingFast — hands-on lessons with examples you run in your browser, plus practice exercises and a quick quiz.

1. The Object Pipeline

In a traditional shell the pipe | passes text , so the next command must re-parse that text every time. PowerShell's pipe passes objects — structured .NET values with named properties (like Name , CPU , Id ) and methods. That single difference is the whole point of the language: you filter, sort, and select by property name instead of counting columns. Where-Object keeps or drops objects, Sort-Object orders them, and Select-Object picks the columns you care about. Read this worked example, then run it.

Order matters and reads left to right: filter first so later steps do less work, then sort, then select. The Where-Object CPU -gt 1 form (property, operator, value) is the easy way to filter on a single property — no $_ needed.

2. Discover Anything with Get-Member

You never have to guess what an object can do. Pipe any object into Get-Member (alias gm ) and it lists every property and method, with types. Properties are the data ( Name , CPU ); methods are actions you call with () ( ToUpper() , GetType() ). This is the most important habit in PowerShell — when you're stuck, Get-Member tells you exactly what's available.

Notice ... inside the string — that's a subexpression : it runs code and drops the result into the text. Use it whenever you need a property or a method call inside "double quotes" .

The pipeline below is almost done. Fill in the two ___ blanks with the property name to filter and sort on, then run it and check your output against the expected lines.

3. ForEach-Object and the $_ Variable

ForEach-Object (alias % ) runs a script block — code in {' curly braces '} — once for every object in the pipeline. Inside that block, $_ (also written $PSItem ) is the current object , exactly like "this item" in a loop. The same $_ appears in any Where-Object {' ... '} script block too. Get comfortable with it now: $_ is everywhere in PowerShell.

Fill in the one blank so each price is multiplied by 1.2 (adding 20% tax). The hint tells you what ___ should be.

4. Calculated Properties

Select-Object doesn't only pick existing columns — it can build new ones . A calculated property is a small hashtable with two keys: Name (the column label) and Expression (a script block that computes the value, using $_ for the current object). This is how you turn raw bytes into megabytes, or a date into "days ago", right in the pipeline.

5. Group-Object & Measure-Object

Because the pipeline carries real data, you can do analysis without exporting to a spreadsheet. Group-Object buckets objects by a property (how many per region?). Measure-Object computes statistics in a single pass: -Sum , -Average , -Maximum , -Minimum , and a plain count. Together they answer real questions straight from the shell.

Here's the same job done the bash way (slicing text with awk ) versus the PowerShell way (naming a property). The bash version breaks the moment a column shifts or a name contains a space; the PowerShell version can't, because it never looks at text positions at all.

No blanks this time — just a brief and an outline. Build the full pipeline yourself: filter, sort, then select with a calculated Status column. Run it and check your output against the expected lines in the comments.

Practice quiz

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