i have a script to gather computer information
$cpus = get-ciminstance -classname Win32_Processor |select-object -Property DeviceID, Name |Export-Csv -Path $cpusfile
$ccpus = Import-Csv -Path $cpusfile
$pcpus = Import-Csv -Path $pcpusfile # this is a copy of the same file from the previous check
$cpuchanges = Compare-Object -ReferenceObject $pcpus -DifferenceObject $cpus -PassThru | Where-Object{$.SideIndicator -eq ‘=>’}
it comes back empty
if i export to txt files and do the same is works. i verified that the variables contain the correct data but with the csv import it does not find the differences.
the only way i found this to work with the csv files if I do
Compare-Object -ReferenceObject (get-ciminstance -classname Win32_Processor) -DifferenceObject (import-csv -Path $pcpusfile) -PassThru |Where-Object {$.sideindicator -eq ‘=>’}
I’m not sure what I am missing. found lots of articles where people do the same kind of import-csv and then compare-objects and seems to work. any help is greatly appreciated
Thorsten,
Welcome back to the forum. 
Long time no see.
First of all … when you post code, sample data, console output or error messages please format it as code using the preformatted text button ( </> ). Simply place your cursor on an empty line, click the button and paste your code.
Thanks in advance
How to format code in PowerShell.org 1 <---- Click 
(Sometimes the “preformatted text” button hides behind the settings gear symbol. )
You import the CSV files into the two variables $ccpus and $pcpus and then you use the variable $cpus for the comparison?! … have you been aware of that? Was that on purpose? I’d recommend longer and more verbose variable names to avoid those kind of confution in general.
Sorry haven’t been here in a while and forgot about the code syntax, thank you for the reminder
this is a script i use as a nagios plugin
on the first check it gathers the cpu info , ($cpus) then at the end of the scripts it saves $cpus to the file that becomes the baseline for the next check. ($pcpus)
the $cpus is the import of the current cpu check and $pcpus is the import from the previous check.
so to test it i can simply modify the file that is imported to $pcpus to force compare-object to detect the change. so $cpus and $pcus contain different data. if done via txt file import it works, if done via csv file import to the variable the compare-object is empty
you can test it just by running the
$cpus = get-ciminstance -classname Win32_Processor |select-object -Property DeviceID, Name
export this to a csv file, make a copy of that file and slightly modify the data
import-that modified file to another variable, now compare-object those to variables.
thank you
That’s my code …
Get-CimInstance -ClassName Win32_Processor |
Select-Object -Property DeviceID, Name |
Export-Csv -Path .\CPU_01.csv -NoTypeInformation
Get-CimInstance -ClassName Win32_Processor |
Select-Object -Property DeviceID, Name |
Export-Csv -Path .\CPU_02.csv -NoTypeInformation
Now I changed the Name property in the second CSV file
$CPU_01 = Import-Csv -Path .\CPU_01.csv
$CPU_02 = Import-Csv -Path .\CPU_02.csv
$CompareObjectSpalt = @{
ReferenceObject = $CPU_01
DifferenceObject = $CPU_02
Property = 'Name'
PassThru = $true
}
Compare-Object @CompareObjectSpalt
And that’s the ouptut:
DeviceID Name SideIndicator
-------- ---- -------------
CPU0 11th Gen Intel(R) Core(TM) i5-1240P =>
CPU0 12th Gen Intel(R) Core(TM) i5-1240P <=
I’m not using a property in the compare-object , could that be the issue?
What could happen when you tried? 
testing that right now
that was the issue. as soon as i added the -property ‘name’ it worked. thank you for your help. i didn’t get that from the documentation and what is still confusing is the difference between importing as text vs csv. it must be different objects in the array?