# The Pipeline

Hand whole objects from one command to the next, and filter, sort, count and group them on the way.

Updated: November 10, 2026

## [Passing Objects](https://www.ask-codey.com/courses/powershell-in-depth/topics/powershell-passing-objects)

1. [The Pipeline: |](https://www.ask-codey.com/lessons/powershell-the-pipeline) (Apprentice): The pipe, |, hands every object one command makes to the next command whole, with all its properties, so you can build a job out of small steps and read it from left to right.

## [Filter, Sort, Count](https://www.ask-codey.com/courses/powershell-in-depth/topics/powershell-filter-sort-count)

1. [Filtering: Where-Object and Comparisons](https://www.ask-codey.com/lessons/powershell-where-object) (Apprentice): Where-Object keeps only the objects that pass a test, such as every file over 1 MB or every song, and the test is written with comparisons read aloud as words, -eq "equals", -gt "greater than", -like "is like", with $\_ standing for this item.
2. [Sorting: Sort-Object](https://www.ask-codey.com/lessons/powershell-sort-object) (Apprentice): Sort-Object puts objects in order by any property, smallest or A first unless you add -Descending, and with Select-Object -First after it gives you the top ten of anything, such as the ten biggest files on a drive; -Unique lists each value once.
3. [Counting and Grouping: Measure-Object and Group-Object](https://www.ask-codey.com/lessons/powershell-measure-and-group) (Apprentice): Measure-Object counts the objects a pipeline hands it and adds up, averages or finds the largest of one property, such as the total size of every file, and Group-Object sorts objects into piles by a property, such as one pile per file type, each with a count.

## [Acting on Each](https://www.ask-codey.com/courses/powershell-in-depth/topics/powershell-acting-on-each)

1. [Doing Something to Each: ForEach-Object](https://www.ask-codey.com/lessons/powershell-foreach-object) (Apprentice): ForEach-Object runs a script block once for every object the pipeline hands it, with $\_ as this item, so one line can rename 200 photos, and -WhatIf goes inside the braces, on the command that makes the change, so you can rehearse first.
2. [Columns You Make Yourself: Calculated Properties](https://www.ask-codey.com/lessons/powershell-calculated-properties) (Journeyman): A calculated property is a column you add to Select-Object yourself, written as a hashtable with a Name for the heading and an Expression that works the value out for each object, such as a file's size in megabytes, rounded with \[math\]::Round.

## [Exercise: The Ten Biggest Files](https://www.ask-codey.com/courses/powershell-in-depth/topics/exercise-powershell-the-ten-biggest-files)

1. [Exercise: The Ten Biggest Files](https://www.ask-codey.com/lessons/exercise-powershell-the-ten-biggest-files) (Apprentice): Find out what's filling a full laptop's 24 made-up files with the pipeline (a count, the ten biggest, the big videos, the files of each type and a table of sizes in KB, each saved as a report) and rename its screenshots with ForEach-Object, while a Pester check tells you which answers are right.

Source: https://www.ask-codey.com/courses/powershell-in-depth/chapters/powershell-the-pipeline