PowerShell Select-Xml
last modified February 15, 2025
In this article, we will cover the Select-Xml cmdlet in
PowerShell. This cmdlet searches XML documents for text matching XPath
queries. It's essential for XML parsing and data extraction tasks.
XML basics
XML (eXtensible Markup Language) is a structured data format. It uses tags
to define elements and attributes to store additional information. PowerShell
provides several ways to work with XML files. The Select-Xml
cmdlet is specifically designed for querying XML content.
Basic Select-Xml usage
The simplest way to use Select-Xml is with a file path and
XPath query. The cmdlet returns matching nodes as XML objects. You can
access node properties and methods for further processing.
Select-Xml -Path "config.xml" -XPath "//book"
This command searches config.xml for all book elements. The double slash in XPath means "search at any level". Each match is returned as a node object with properties.
Selecting specific attributes
You can extract specific attributes from XML elements using XPath. The @ symbol in XPath refers to attributes. This is useful when you need only certain data from complex XML structures.
Select-Xml -Path "data.xml" -XPath "//person/@id"
This command retrieves all id attributes from person elements in data.xml. The output shows attribute values. You can pipe results to other cmdlets for processing.
PS C:\> .\xml2.ps1 Node Path Pattern ---- ---- ------- id data.xml //person/@id id data.xml //person/@id
Using XML content directly
Instead of file paths, you can pass XML content directly to Select-Xml. Use the -Content parameter with a string containing XML. This works well for small XML fragments or dynamically generated XML.
$xml = "<books><book id='101'>PowerShell Guide</book></books>" Select-Xml -Content $xml -XPath "//book"
This example searches XML content stored in a variable. The command finds the book element and returns its details. No external file is needed.
Working with namespaces
XML documents often use namespaces to avoid element name conflicts. To query these, you must specify namespace mappings. Use the -Namespace parameter with a hashtable of prefix-URI pairs.
$ns = @{ns="http://example.com/books"}
Select-Xml -Path "catalog.xml" -XPath "//ns:book" -Namespace $ns
This command searches for book elements in a namespace. The ns prefix maps to the specified URI. Without proper namespace handling, queries would fail to match elements.
Filtering with XPath conditions
XPath supports conditional expressions for filtering nodes. You can check attribute values, element content, or positions. This allows precise targeting of specific XML data.
Select-Xml -Path "inventory.xml" -XPath "//item[price > 100]"
This example finds item elements where price is greater than 100. The condition is specified in square brackets. Multiple conditions can be combined with and/or operators.
Accessing node values
To extract text content from nodes, use the Node property of results. Each match object has Node with the actual XML node. You can access its InnerText or other properties.
(Select-Xml -Path "notes.xml" -XPath "//title").Node.InnerText
This command gets the text content of title elements. The parentheses ensure we access Node after query execution. InnerText contains all text within the element.
Combining with other cmdlets
Select-Xml results can be piped to other cmdlets for processing. For example, you might format output or export data. This enables complex XML processing workflows.
Select-Xml -Path "employees.xml" -XPath "//employee" |
ForEach-Object { $_.Node.name }
This pipeline extracts names from employee elements. ForEach-Object processes each match. The $_ variable represents the current object.
Source
In this article, we have covered the Select-Xml cmdlet in PowerShell.
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