Powershell command -- To add a attribute if not exist in a particular node of a XML - string

Question

<APPPOOL APPPOOL.NAME="Classic" RuntimeVersion="v2.0" state="Started">
<add name="Classic" autoStart="true" managedRuntimeVersion="v2.0">
<APPPOOL APPPOOL.NAME="GetServiceDet" RuntimeVersion="v2.0" state="Started">
<add name="GetServiceDet" autoStart="true">
my file has many line begining with word "add name".
I want to check if these lines have a string "managedRuntimeVersion".
if not exists, then i need to add managedRuntimeVersion="v2.0" to
that line.
Expected Result as below
<APPPOOL APPPOOL.NAME="Classic" RuntimeVersion="v2.0" state="Started">
<add name="Classic" autoStart="true" managedRuntimeVersion="v2.0">
<APPPOOL APPPOOL.NAME="GetServiceDet" RuntimeVersion="v2.0" state="Started">
<add name="GetServiceDet" autoStart="true" managedRuntimeVersion="v2.0">
I have tried with the below script.. but in the result.. it is given only the lines having "add name"
$sfile="C:\Users\subash.s\Desktop\backup\pool.xml"
(((gc "$sfile") | Select-String -Pattern "add name" |
select-string -notmatch "managedRuntimeVersion") -replace '>',' managedRuntimeVersion="v2.0">') |
Set-Content "$sfile"
with the above script. i got below result..
<add name="Classic" autoStart="true" managedRuntimeVersion="v2.0">
<add name="GetServiceDet" autoStart="true" managedRuntimeVersion="v2.0">

Answer 1

For Pete's sake, the configuration file is XML, not a text file! Edit it as an XML document, and you will save a lot of headaches.
There are a few ways to add attributes into such a document. As the XML in the question is a fragment - and of illegal syntax, the sample code uses a bit modified version of the same. Select all add nodes that don't have got managedRuntimeVersion attribute, create one and add attribute with values to the nodes. Like so,
# Dummy data for testing
[xml]$x = #'
<root>
<APPPOOL APPPOOL.NAME="GetServiceDet" RuntimeVersion="v2.0" state="Started">
<add name="GetServiceDet2" autoStart="true"/>
</APPPOOL>
<APPPOOL APPPOOL.NAME="Classic" RuntimeVersion="v2.0" state="Started">
<add name="Classic" autoStart="true" managedRuntimeVersion="v2.0" />
</APPPOOL>
<APPPOOL APPPOOL.NAME="GetServiceDet" RuntimeVersion="v2.0" state="Started">
<add name="GetServiceDet" autoStart="true"/>
</APPPOOL>
</root>
'#
# Select all add elements that don't have managedRuntimeVersion attribute
$nl=$x.SelectNodes('/root/APPPOOL/add[not(#managedRuntimeVersion)]')
# Add attributes to the elements
foreach($n in $nl) {
# Create new attribute and assign a value
$a = $x.CreateAttribute('managedRuntimeVersion')
$a.Value = 'v2.0'
[void]$n.Attributes.Append($a)
}
# Print modified version to console
$x.save([console]::out)
# Output
<?xml version="1.0" encoding="ibm850"?>
<root>
<APPPOOL APPPOOL.NAME="GetServiceDet" RuntimeVersion="v2.0" state="Started">
<add name="GetServiceDet2" autoStart="true" />
</APPPOOL>
<APPPOOL APPPOOL.NAME="Classic" RuntimeVersion="v2.0" state="Started">
<add name="Classic" autoStart="true" managedRuntimeVersion="v2.0" />
</APPPOOL>
<APPPOOL APPPOOL.NAME="GetServiceDet" RuntimeVersion="v2.0" state="Started">
<add name="GetServiceDet" autoStart="true" managedRuntimeVersion="v2.0" />
</APPPOOL>
</root>
Reading the actual file and saving changes to disk are left as an exercise to the reader.