6 The pipeline: connecting commands

PowerShell’s distinctive power comes from its pipeline, which lets you connect commands so the output of one becomes the input of the next, enabling compact, task-focused one-liners. Unlike traditional text-based shells, this pipeline passes rich objects, making downstream processing more precise and flexible. You learn to chain commands for viewing, exporting, converting, formatting, and even modifying system state, all by composing small, single-purpose cmdlets. The result is a clear model: gather data, transform or format it, and direct it to a destination.

The chapter shows practical exporting patterns: use Export-CSV to capture flat object data, then Import-CSV to bring it back as objects (contrasting that with Get-Content, which returns raw text). When nested properties matter (for example, process Threads), ConvertTo-Json and ConvertFrom-Json preserve structure, though the returned objects won’t be the original types. Export-Clixml and Import-Clixml keep type fidelity so PowerShell can reconstruct original objects, at the cost of larger, PowerShell-specific files and potential encryption of sensitive data on Windows. With these formats you can create snapshots, share them, and compare states using Compare-Object, focusing on relevant properties (such as Name) to avoid noisy differences.

You also learn how to redirect and format output: > is shorthand for piping to Out-File, which supports width and encoding controls; Out-Default routes to Out-Host when you don’t specify otherwise. ConvertTo-Html produces browser-friendly reports that you save with Out-File, and similar ConvertTo-* cmdlets (CSV, XML) convert without writing files, whereas Export-* both convert and save. Pipelines can drive action too, such as passing Get-Process results to Stop-Process, with safety features like -Confirm, -WhatIf, and the $ConfirmPreference impact model. The chapter clears common confusions (for example, why Import-CSV, not Get-Content, is used to read CSV data) and highlights useful parameters like IncludeTypeInformation, delimiter customization, and culture-aware settings—reinforcing that the pipeline is about composing reliable, readable building blocks to get real work done.

The output of Get-Process is a table with several columns of information.

Viewing the exported CSV file in Windows Notepad

1. PS C:\Scripts > "I am the walrus" | Out-File file1.txt

2. If you don’t specify a filename with Out-File, you’ll get an error. But even if you do, Out-File won’t do anything because the file is created by Export-CSV.
3. Stop-Job can accept one or more job names as parameter values for the –Name parameter. For example, you could run this:

4. get-Command | Export-CSV commands.CSV -Delimiter "|"
5. Use the –IncludeTypeInformation parameter with Export-CSV.
6. Get-Command | Export-CSV services.CSV –NoClobber

7. Get-Command | Export-CSV services.CSV -UseCulture

FAQ

Get-Process | Export-CSV procs.csv

Get-Process | ConvertTo-Json | Out-File procs.json
Get-Process | Export-Clixml procs.xml

Get-Content procs.json | ConvertFrom-Json
Import-Clixml procs.xml

# Writes a file
Get-Process | Export-CSV procs.csv

# Emits HTML to pipeline; use Out-File to save
Get-Process | ConvertTo-Html | Out-File processes.html

Get-Command | Export-CSV commands.csv

Get-Process | Out-File processes.txt -Width 200
# or
Get-Process > processes.txt

Get-Process | Export-Clixml reference.xml
Compare-Object -ReferenceObject (Import-Clixml reference.xml) `
               -DifferenceObject (Get-Process) `
               -Property Name

Import-CSV .\processes.csv

Export-CSV .\processes.csv -IncludeTypeInformation

# Narrow the target
Get-Process -Name bash | Stop-Process

# Always ask
Get-Process -Name bash | Stop-Process -Confirm

# Dry run
Get-Process -Name bash | Stop-Process -WhatIf

# Check the confirmation threshold
$ConfirmPreference  # typically "High"

Get-Command | Export-CSV cmds.csv -NoClobber -UseCulture
Get-Process | Export-CSV procs.psv -Delimiter '|'