# The Pipeline: | 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. Apprentice · PowerShell · Operating System · Updated November 10, 2026 ## After this lesson you can - Pass objects from one command to the next with the pipe, and read a pipeline from left to right - Explain why an object that arrives through the pipe still has all its properties, such as Length and LastWriteTime ## Key takeaways - `|` (read "pipe") hands what one command makes to the next command. A pipeline is read from left to right. - The objects that arrive are whole. A file still has its Name, Length and LastWriteTime, so the next command can sort or filter by them. - Build a pipeline one step at a time. Run the first command, look at what it gives you, then add the next step. - Commands that change things, such as Remove-Item and Stop-Process, take what arrives through the pipe. Rehearse them with -WhatIf. Your laptop says the disk is almost full. In File Explorer you can sort one folder by size, then the next folder, then the next, and try to keep the biggest files in your head. What you want is one list: the biggest files anywhere on the drive. No single command gives you that, but three small ones in a row do, each handing its results to the next. That handing-on is the **pipeline**, and this whole chapter is built on it. An IT help-desk tech uses it to find what's filling someone's drive; a web developer uses it to find the images that make a page slow. ## First, a practice drive This chapter works in a pretend drive: a `drive` folder with five folders inside and eighteen made-up files of different sizes. Copy these lines into PowerShell and press Enter. They make the folder, go into it and fill it. Running them again is safe: they write the same files again. ```powershell New-Item -ItemType Directory -Force -Path "$HOME\terminal-practice\drive" | Out-Null Set-Location "$HOME\terminal-practice\drive" New-Item -ItemType Directory -Force -Path documents, downloads, music, photos, videos | Out-Null Set-Content documents\budget-2026.xlsx ('x' * 48KB) -NoNewline Set-Content documents\resume.docx ('x' * 36KB) -NoNewline Set-Content documents\shopping-list.txt 'milk, eggs, bread, apples, coffee' Set-Content documents\tax-return-2025.pdf ('x' * 420KB) -NoNewline Set-Content downloads\class-notes.pdf ('x' * 610KB) -NoNewline Set-Content downloads\game-setup.exe ('x' * 2300KB) -NoNewline Set-Content downloads\phone-backup.zip ('x' * 1900KB) -NoNewline Set-Content downloads\unfinished-download.tmp ('x' * 1100KB) -NoNewline Set-Content music\rain-sounds.mp3 ('x' * 1300KB) -NoNewline Set-Content music\ringtone.mp3 ('x' * 150KB) -NoNewline Set-Content music\road-trip-mix.mp3 ('x' * 1700KB) -NoNewline Set-Content photos\beach-sunset.jpg ('x' * 850KB) -NoNewline Set-Content photos\birthday-cake.png ('x' * 520KB) -NoNewline Set-Content photos\dog-in-the-snow.jpg ('x' * 960KB) -NoNewline Set-Content photos\recipe-screenshot.png ('x' * 130KB) -NoNewline Set-Content videos\birthday-party.mp4 ('x' * 1500KB) -NoNewline Set-Content videos\cat-and-the-cucumber.mp4 ('x' * 700KB) -NoNewline Set-Content videos\graduation.mp4 ('x' * 2800KB) -NoNewline ``` They print nothing when they work. Each pretend file holds only the letter x, over and over: `'x' * 2800KB` is 2,800 kilobytes of x's, standing in for a real video. `KB` (read "kilobytes") and `MB` ("megabytes") are sizes PowerShell knows: `1KB` is 1,024 bytes and `1MB` is 1,024 KB. The drive takes about 17 MB; delete the `drive` folder when you finish the chapter. ## One command's results into the next: | In a restaurant kitchen, one cook puts the food on a plate and slides it through the pass, a shelf between two stations. The next cook picks up the plate and adds the sauce. The **pipe**, `|` (read "pipe"; on most keyboards it's Shift and the backslash key), is that pass: it hands everything the command on its left makes to the command on its right. ```powershell Get-ChildItem -Recurse -File | Select-Object -First 3 ``` ```text Directory: C:\Users\Sam\terminal-practice\drive\documents Mode LastWriteTime Length Name ---- ------------- ------ ---- -a--- 9/14/2026 6:30 PM 49152 budget-2026.xlsx -a--- 9/14/2026 6:30 PM 36864 resume.docx -a--- 9/14/2026 6:30 PM 35 shopping-list.txt ``` Read it from left to right: get every file in this folder and in every folder inside it (`-Recurse`), then keep the first three. `Select-Object -First` is from *Picking Columns: Select-Object*. Your dates will be the moment you made the files. ## The whole plate, not a photo of it The cook hands over the plate itself, not a photo of the plate. What arrives after a pipe is the same: the file itself, with every fact it had. `Get-Member`, from *What an Object Is: Get-Member*, shows it: ```powershell Get-ChildItem -Recurse -File | Select-Object -First 1 | Get-Member -Name Name, Length, Extension, LastWriteTime ``` ```text TypeName: System.IO.FileInfo Name MemberType Definition ---- ---------- ---------- Name Property string Name {get;} Length Property long Length {get;} Extension Property string Extension {get;} LastWriteTime Property datetime LastWriteTime {get;set;} ``` After two pipes, it's still a `FileInfo`, a file, with its Length and LastWriteTime. That's what makes PowerShell's pipeline special, and why it's called an **object pipeline**. In many other shells a pipe passes lines of text, and the next command has to dig the size out of each line by where it sits. In PowerShell the next command asks for `Length` by name. ## Build it one step at a time Here are the three biggest files on the drive: ```powershell Get-ChildItem -Recurse -File | Sort-Object Length -Descending | Select-Object -First 3 Name, Length ``` ```text Name Length ---- ------ graduation.mp4 2867200 game-setup.exe 2355200 phone-backup.zip 1945600 ``` Read it aloud: "Get every file, pipe, sort them by Length, biggest first, pipe, keep the first three, with their Name and Length." *Sorting: Sort-Object*, two lessons on, teaches the middle step. ![The pipeline as a kitchen line: Get-ChildItem hands whole files, each still carrying its Name, Length and LastWriteTime, through a pass marked | to Sort-Object, which puts them biggest first and hands them through a second | to Select-Object -First 3, which keeps graduation.mp4, game-setup.exe and phone-backup.zip](https://fsdtrainingmedia.blob.core.windows.net/public/images/2026/11/0df50f76621d413db8fa92d10675ddeb.webp) Nobody writes that in one go. Run `Get-ChildItem -Recurse -File` alone and look. Press the up arrow, add `| Sort-Object Length -Descending`, and look again. Then add the last step. When a result looks wrong, the step you added last is where to look. A long pipeline can also go over several lines: end a line with `|` and press Enter, and PowerShell shows `>>` and waits for the rest. ## Commands that act on what arrives Commands that change things take what arrives through the pipe, too. `Remove-Item` removes every file it's handed, so rehearse with `-WhatIf` first, as in *Deleting Safely: Remove-Item, -WhatIf and -Confirm*: ```powershell Get-ChildItem downloads\*.tmp | Remove-Item -WhatIf ``` ```text What if: Performing the operation "Remove File" on target "C:\Users\Sam\terminal-practice\drive\downloads\unfinished-download.tmp". ``` Running programs are objects too. `Get-Process -Name explorer` gets File Explorer, which also draws the taskbar, and `Stop-Process` stops whatever it's handed: ```powershell Get-Process -Name explorer | Stop-Process -WhatIf ``` ```text What if: Performing the operation "Stop-Process" on target "explorer (7404)". What if: Performing the operation "Stop-Process" on target "explorer (61600)". What if: Performing the operation "Stop-Process" on target "explorer (87772)". ``` The number in brackets is each program's Id; you may have one explorer or several, with other numbers. Keep `-WhatIf` on this one: without it, your Explorer windows and the taskbar close until Windows starts them again. Windows PowerShell 5.1 runs all of this the same way. On a Mac or Linux there's no explorer: try `Get-Process -Name pwsh | Stop-Process -WhatIf` instead, and write paths with `/`. **Try it.** Build the pipeline for the three *smallest* files, one step at a time: start with `Get-ChildItem -Recurse -File`, then add the sort (without `-Descending`), then the last step. ## Check yourself 2 questions to try on the lesson page. ## So what One command answers one question. The pipe lets small commands answer a big one together, and because each step hands on whole objects, the next step can use any fact about them. ## Key terms - [Pipeline](https://www.ask-codey.com/glossary/pipeline) - [Object Pipeline](https://www.ask-codey.com/glossary/object-pipeline) - [Pipeline Input Binding](https://www.ask-codey.com/glossary/pipeline-input-binding) - [-WhatIf and -Confirm](https://www.ask-codey.com/glossary/whatif-and-confirm) ## Cheat sheets - [The Pipeline: |](https://www.ask-codey.com/cheat-sheets/powershell-the-pipeline-cheat-sheet) ## Related - [What an Object Is: Get-Member](https://www.ask-codey.com/lessons/powershell-what-is-an-object) - [Picking Columns: Select-Object](https://www.ask-codey.com/lessons/powershell-select-object) - [Filtering: Where-Object and Comparisons](https://www.ask-codey.com/lessons/powershell-where-object) - [Sorting: Sort-Object](https://www.ask-codey.com/lessons/powershell-sort-object) Source: https://www.ask-codey.com/lessons/powershell-the-pipeline