Colleagues, what I need is to get the list of mailboxes based on domain\logon name only. Shared mailboxes contain mostly the users that are located on other domains hence I have to use command for getting the data for linked accounts.

First of all I export the list of names to a csv file.

Get-Mailbox -Identity GROUP  | Get-MailboxPermission | where {$_.user.tostring() -ne "NT AUTHORITY\SELF" -and $_.IsInherited -eq $false} | Export-csv -path C:\Users\mplumsky\Desktop\GROUP_list.csv NoTypeInformation

When I try the following command on a single user it works well:

get-mailbox -Resultsize Unlimited | ? { $_.LinkedMasterAccount -eq 'domain\user' }  | select Name, Primarysmtpaddress > mailbox.txt

Of course I have a long list of users and it would be great when powershell could do the job in the background. That's why I've come up with the idea:

$users = import-csv C:\Users\mplumsky\Desktop\GROUP_list.csv

ForEach ($item in $users)

{

$username = $item.User

get-mailbox -Resultsize Unlimited | ? { $_.LinkedMasterAccount -eq '$username' }  | select Name, Primarysmtpaddress > mailbox_list.csv

}

As a result I get a blank csv or txt file. Any ideas what could be wrong?

I've not tested it, but as a first try: I think ">" overwrites existing files. Use Cmdlet "Add-Content" instead. Of course you have to ensure that the file exists before with "Test-Path" and "New-Item" if needed. Another way would be to store everything in an array and use "Export-CSV" for output.

Furthermore, I think it doesn't make sense to run Get-Mailbox in every turn of the loop, if there is no depended parameter. Do that before the foreach-loop and only call the variable inside.

import-csv C:\Users\mplumsky\Desktop\GROUP_list.csv |
    ForEach-Object{
        $username=$_.User
        get-mailbox -Resultsize Unlimited | ? { $_.LinkedMasterAccount -eq $username }  
    } |
    select Name, Primarysmtpaddress |
    Export-Csv mailbox_list.csv