How to compare two xml files and display the difference side by side.

jos07 

I did some more experimenting ... hope the code comments explain what is being done

# set up two xml variables
# the equivalent for you would be [xml] (get-content <xmlfilepath>)
[xml]$doc1 = @"
<geography>
<country>
    <name>UK</name>
    <capital>London</capital>
</country>
<country>
    <name>France</name>
    <capital>Paris</capital>
</country>
</geography>
"@

[xml]$doc2 = @"
<geography>
<country>
    <name>Germany</name>
    <capital>Berlin</capital>
</country>
<country>
    <name>UK</name>
    <capital>London</capital>
</country>
<country>
    <name>Italy</name>
    <capital>Rome</capital>
</country>
</geography>
"@

# because the two variables are [xml] data type we can now use xml notation to reference the parts we want to compare - here compare country names
compare-object -referenceobject $doc1.geography.country.name -differenceobject $doc2.geography.country.name

<#
InputObject SideIndicator
----------- -------------
Germany     =>
Italy       =>
France      <=
#>

# here compare country capitals
compare-object -referenceobject $doc1.geography.country.capital -differenceobject 
$doc2.geography.country.capital
<#
InputObject SideIndicator
----------- -------------
Berlin      =>
Rome        =>
Paris       <=
#>

# now there is also the Select-Xml which is a bit less specific
$Doc1Capitals = Select-Xml -Xml $doc1 -XPath "//capital"| foreach {$_.node.InnerXML}
$Doc2Capitals = Select-Xml -Xml $doc2 -XPath "//capital"| foreach {$_.node.InnerXML}
# so when we compare those varaibles we can get the same output
compare-object $Doc1Capitals $Doc2Capitals
<#
InputObject SideIndicator
----------- -------------
Berlin      =>
Rome        =>
Paris       <=
#>

hope this gives you a boost but I fear you are working with complex XML and the parsing and evaluation will be difficult