Vista Tutorial - Variable issues within pipeline using wmi

Hi,

I have been messing around with trying to create a single line command to
list logged on users to a machine. I think this should be quiet easy but I
am struggling with the way powershell is handling my variable expansion
within the pipeline.

I expect this command to work, however it doesn't seem to expand the
variable correctly.

gwmi -query "Select logonid from Win32_LogonSession where logontype = 2 or
logontype = 10" -computername aupoza510 | foreach {gwmi -computername
aupoza510 -query 'Associators of {Win32_LogonSession.LogonId=$_.logonid}
Where AssocClass=Win32_LoggedOnUser Role=Dependent'}


The following command does work ... seems very strange to me.

gwmi -query "Select logonid from Win32_LogonSession where logontype = 2 or
logontype = 10" -computername aupoza510 | foreach {gwmi -computername
aupoza510 -query "Associators of{$_} Where AssocClass=Win32_LoggedOnUser
Role=Dependent"}

The other thing I have found strange which is not related to powershell is
that the logontype does not seem correct all the time. I ran the command
against the server where I was terminal serviced in (logontype 10) and it
didn't return my logon. I then checked on the server and my logontype was 0
which is meant to be reserved for the system. Any ideas?

Cheers,

Adam.

"Adam Murray" <muzzar78@msn.com> wrote in message
news:Ot4O9CGCHHA.204@TK2MSFTNGP04.phx.gbl...
> I have been messing around with trying to create a single line command to
> list logged on users to a machine. I think this should be quiet easy but I
> am struggling with the way powershell is handling my variable expansion
> within the pipeline.
>
> I expect this command to work, however it doesn't seem to expand the
> variable correctly.
>
> gwmi -query "Select logonid from Win32_LogonSession where logontype = 2 or
> logontype = 10" -computername aupoza510 | foreach {gwmi -computername
> aupoza510 -query 'Associators of {Win32_LogonSession.LogonId=$_.logonid}
> Where AssocClass=Win32_LoggedOnUser Role=Dependent'}

Using single quotes tells PowerShell to not perform variable substituion.
So on that last query (where you use $_.logonid) you probably want to use
double qoutes.

--
Keith

"Keith Hill [MVP]" <r_keith_hill@mailhot.moc.nospam> wrote in message
news:%23517AtHCHHA.4464@TK2MSFTNGP06.phx.gbl...
> "Adam Murray" <muzzar78@msn.com> wrote in message
> news:Ot4O9CGCHHA.204@TK2MSFTNGP04.phx.gbl...
>> gwmi -query "Select logonid from Win32_LogonSession where logontype = 2
>> or logontype = 10" -computername aupoza510 | foreach {gwmi -computername
>> aupoza510 -query 'Associators of {Win32_LogonSession.LogonId=$_.logonid}
>> Where AssocClass=Win32_LoggedOnUser Role=Dependent'}
>
> Using single quotes tells PowerShell to not perform variable substituion.
> So on that last query (where you use $_.logonid) you probably want to use
> double qoutes.

Oh yeah, to not only expand variables but then to reference a property on
that variable you need to do this:

$($_.logonid)

That tells PowerShell to evaluate the entire expression in $(...) instead of
evaluating $_ and then appending the string ".logonid" to it.

--
Keith

Thanks Keith.


"Keith Hill [MVP]" <r_keith_hill@mailhot.moc.nospam> wrote in message
news:%23kcoaDJCHHA.4060@TK2MSFTNGP03.phx.gbl...
> "Keith Hill [MVP]" <r_keith_hill@mailhot.moc.nospam> wrote in message
> news:%23517AtHCHHA.4464@TK2MSFTNGP06.phx.gbl...
>> "Adam Murray" <muzzar78@msn.com> wrote in message
>> news:Ot4O9CGCHHA.204@TK2MSFTNGP04.phx.gbl...
>>> gwmi -query "Select logonid from Win32_LogonSession where logontype = 2
>>> or logontype = 10" -computername aupoza510 | foreach
>>> {gwmi -computername aupoza510 -query 'Associators of
>>> {Win32_LogonSession.LogonId=$_.logonid} Where
>>> AssocClass=Win32_LoggedOnUser Role=Dependent'}
>>
>> Using single quotes tells PowerShell to not perform variable substituion.
>> So on that last query (where you use $_.logonid) you probably want to use
>> double qoutes.
>
> Oh yeah, to not only expand variables but then to reference a property on
> that variable you need to do this:
>
> $($_.logonid)
>
> That tells PowerShell to evaluate the entire expression in $(...) instead
> of evaluating $_ and then appending the string ".logonid" to it.
>
> --
> Keith
>