Get-Mailbox PS command import/export csv - need help

Question

Greetings,
I know this should be simple but I'm having trouble.  I have about 500 users that have left the company and I want to verify their Exchange 2010 mailbox have been disabled.  If I just run the basic command "Get-Mailbox -identity alias"
I see all I need to see.  The Name, Alias, and ServerName (that their mailbox is on).  If I check someone whose mailbox has been disabled I get "object could not be found."  Perfect, then I know their mailbox no longer exists. 
In trying to import a csv file of the 500 users - and export it I'm having trouble. There are a few posts on these forums for similar issues but none are working or the conditions are different.  I'm not too good and PS scripting so I am hoping someone
can assist.  I pieced this together.
import-csv C:\temp\DisabledMBs.csv | get-mailbox >c:\temp\DisabledMBsOutput.csv
The csv output file is blank.  The PS screen outputs this error for each user.
The input object cannot be bound to any parameters for the command either because the command does not take pipeline input or the input and its properties do not match any of the parameters that take pipeline input.
    + CategoryInfo          : InvalidArgument: (@{Name=Heaton; ...er Logon Name=}:PSObject) [Get-Mailbox], ParameterBindingException
    + FullyQualifiedErrorId : InputObjectNotBound,Get-Mailbox
I guess I'm missing something here but stuck.  Any help is greatly appreciated!
thank you!

Answer 1

If you use a CSV for input, you need to tell the Get-Mailbox command what field is the identifier.  So if you have an alias field in your CSV, you would run your command as follows:
import-csv C:\temp\DisabledMBs.csv | % { get-mailbox $_.Alias } | Export-Csv c:\temp\DisabledMBsOutput.csv -NoTypeInformation
BTW, you'll notice that I've also piped your output to the Export-Csv command.  If you just pipe the output of Get-Mailbox to a file with a CSV suffix, you don't get a CSV - you get a text file with only one field named "Name                     
Alias                ServerName       ProhibitSendQuota" (note, not "Name", "Alias", "ServerName", and "ProhibitSendQuota"
separately).