How to Use Pipeline in PowerShell: Syntax and Examples

In PowerShell, the | symbol is used to create a pipeline that passes the output of one command as input to the next. This allows chaining commands to process data step-by-step in a simple and readable way.

Syntax

The basic syntax of a PowerShell pipeline uses the | character to connect commands. Each command processes the data and passes it along.

• Command1 | Command2 | Command3: Output of Command1 goes to Command2, then Command2's output goes to Command3.
• Each command receives objects, not just text, allowing powerful data manipulation.

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Get-Process | Where-Object { $_.CPU -gt 100 } | Sort-Object CPU -Descending

Example

This example shows how to list running processes that use more than 100 CPU units, then sort them by CPU usage in descending order.

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Get-Process | Where-Object { $_.CPU -gt 100 } | Sort-Object CPU -Descending | Select-Object -Property Id, ProcessName, CPU

Output

Id    ProcessName       CPU
--    -----------       ---
1234  chrome            250.5
5678  powershell        150.2

Common Pitfalls

Common mistakes when using pipelines include:

• Using commands that output text instead of objects, which can break the pipeline.
• Forgetting to use $_ to refer to the current object in script blocks.
• Assuming output is text rather than structured objects, leading to unexpected results.

Always check if commands output objects and use Where-Object or ForEach-Object properly.

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Get-Process | Where-Object { $_.CPU -gt 100 }  # Correct usage

Get-Process | Where-Object { $_.CPU -gt 100 }      # Incorrect, missing $_

Quick Reference

PowerShell pipeline tips:

• Use | to chain commands.
• Use $_ inside script blocks to refer to the current object.
• Commands pass objects, not just text.
• Use Where-Object to filter objects.
• Use ForEach-Object to perform actions on each object.

Key Takeaways

Use the pipeline symbol | to pass output from one command to another in PowerShell.

PowerShell pipelines pass objects, enabling powerful and flexible data processing.

Inside script blocks, use $_ to refer to the current object in the pipeline.

Common errors include forgetting $_ or using commands that output plain text instead of objects.

Use Where-Object and ForEach-Object to filter and manipulate pipeline data.