I can't seem to get individual elements when comparing 2 arrays using Compare-Object

Question

My backup software keeps track of servers with issues using a 30 day rolling log, which it emails to me once a week in CSV format. What I want to do is create a master list of servers, then compare that master list against the new weekly lists to identify
servers that are not in the master list, and vice versa. That way I know what servers are new problem and which ones are pre-existing and which ones dropped off the master list. At the bottom is the entire code for the project. I know it's a bit much
but I want to provide all the information, hopefully making it easier for you to help me :)
Right now the part I am working on is in the Compare-NewAgainstMaster function, beginning on line 93. After putting one more (fake) server in the master file, the output I get looks like this
Total entries (arrMasterServers): 245
Total entries (arrNewServers): 244
Comparing new against master
There are 1 differences.
InputObject SideIndicator
@{Agent= Virtual Server in vCenterServer; Backupse... <=
What I am trying to get is just the name of the server, which should be $arrDifferent[0] or possibly $arrDifferent.Client. Once I have the name(s) of the servers that are different, then I can do stuff with that. So either I am not accessing the array
right, building the array right, or using Compare-Object correctly.
Thank you!
Sample opening lines from the report
" CommCells > myComCellServer (Reports) >"
" myComCellServer -"
" 30 day SLA"
CommCell Details
" Client"," Agent"," Instance"," Backupset"," Subclient"," Reason"," Last Job Id"," Last Job End"," Last Job Status"
" myServerA"," vCenterServer"," VMware"," defaultBackupSet"," default"," No Job within SLA Period"," 496223"," Nov 17, 2014"," Killed"
" myServerB"," Oracle Database"," myDataBase"," default"," default"," No Job within SLA Period"," 0"," N/A"," N/A"
Entire script
# things to add
# what date was server entered in list
# how many days has server been on list
# add temp.status = pre-existing, new, removed from list
# copy sla_master before making changes. Copy to archive folder, automate rolling 90 days?
## 20150114 Created script ##
#declare global variables
$global:arrNewServers = @()
$global:arrMasterServers = @()
$global:countNewServers = 1
function Get-NewServers
Param($path)
Write-Host "Since we're skipping the 1st 6 lines, create test to check for opening lines of report from CommVault."
write-host "If not original report, break out of script"
Write-Host ""
#skip 5 to include headers, 6 for no headers
(Get-Content -path $path | Select-Object -Skip 6) | Set-Content $path
$sourceNewServers = get-content -path $path
$global:countNewServers = 1
foreach ($line in $sourceNewServers)
#declare array to hold object temporarily
$temp = @{}
$tempLine = $line.Split(",")
#get and assign values
$temp.Client = $tempLine[0].Substring(2, $tempLine[0].Length-3)
$temp.Agent = $tempLine[1].Substring(2, $tempLine[1].Length-3)
$temp.Backupset = $tempLine[3].Substring(2, $tempLine[3].Length-3)
$temp.Reason = $tempLine[5].Substring(2, $tempLine[5].Length-3)
#write temp object to array
$global:arrNewServers += New-Object -TypeName psobject -Property $temp
#increment counter
$global:countNewServers ++
Write-Host ""
$exportYN = Read-Host "Do you want to export new servers to new master list?"
$exportYN = $exportYN.ToUpper()
if ($exportYN -eq "Y")
$exportPath = Read-Host "Enter full path to export to"
Write-Host "Exporting to $($exportPath)"
foreach ($server in $arrNewServers)
$newtext = $Server.Client + ", " + $Server.Agent + ", " + $Server.Backupset + ", " + $Server.Reason
Add-Content -Path $exportPath -Value $newtext
function Get-MasterServers
Param($path)
$sourceMaster = get-content -path $path
$global:countMasterServers = 1
foreach ($line in $sourceMaster)
#declare array to hold object temporarily
$temp = @{}
$tempLine = $line.Split(",")
#get and assign values
$temp.Client = $tempLine[0]
$temp.Agent = $tempLine[1]
$temp.Backupset = $tempLine[2]
$temp.Reason = $tempLine[3]
#write temp object to array
$global:arrMasterServers += New-Object -TypeName psobject -Property $temp
#increment counter
$global:countMasterServers ++
function Compare-NewAgainstMaster
Write-Host "Total entries (arrMasterServers): $($countMasterServers)"
Write-Host "Total entries (arrNewServers): $($countNewServers)"
Write-Host "Comparing new against master"
#Compare-Object $arrMasterServers $arrNewServers
$arrDifferent = @(Compare-Object $arrMasterServers $arrNewServers)
Write-Host "There are $($arrDifferent.Count) differences."
foreach ($item in $arrDifferent)
$item
## BEGIN CODE ##
cls
$getMasterServersYN = Read-Host "Do you want to get master servers?"
$getMasterServersYN = $getMasterServersYN.ToUpper()
if ($getMasterServersYN -eq "Y")
$filePathMaster = Read-Host "Enter full path and file name to master server list"
$temp = Test-Path $filePathMaster
if ($temp -eq $false)
Read-Host "File not found ($($filePathMaster)), press any key to exit script"
exit
Get-MasterServers -path $filePathMaster
$getNewServersYN = Read-Host "Do you want to get new servers?"
$getNewServersYN = $getNewServersYN.ToUpper()
if ($getNewServersYN -eq "Y")
$filePathNewServers = Read-Host "Enter full path and file name to new server list"
$temp = Test-Path $filePathNewServers
if ($temp -eq $false)
Read-Host "File not found ($($filePath)), press any key to exit script"
exit
Get-NewServers -path $filePathNewServers
#$global:arrNewServers | format-table client, agent, backupset, reason -AutoSize
#Write-Host ""
#Write-Host "Total entries (arrNewServers): $($countNewServers)"
#Write-Host ""
#$global:arrMasterServers | format-table client, agent, backupset, reason -AutoSize
#Write-Host ""
#Write-Host "Total entries (arrMasterServers): $($countMasterServers)"
#Write-Host ""
Compare-NewAgainstMaster

Answer 1

do not do this:
$arrDifferent = @(Compare-Object $arrMasterServers $arrNewServers)
Try this:
$arrDifferent = Compare-Object $arrMasterServers $arrNewServers -PassThru
¯\_(ツ)_/¯
This is what made the difference. I guess you don't have to declare arrDifferent as an array, it is automatically created as an array when Compare-Object runs and fills it with the results of the compare operation. I'll look at that "pass thru" option
in a little more detail. Thank you very much!
Yes - this is the way PowerShell works.  You do not need to write so much code once you understand what PS can and is doing.
¯\_(ツ)_/¯