PowerShell -or issue with Get-Smbshare

Question

When i run the following PowerShell (v5) code, the exclusions (C$, ADMIN$, IPC$ are not happening).

$shares = Get-SmbShare | where {$_.Name -ne "IPC$" -or $_.name -ne "C$" -or $_.name -ne "ADMIN$"}
$shares

the output is

Name      ScopeName Path           Description  
----      --------- ----           -----------  
ADMIN$    *         C:\WINDOWS     Remote Admin 
C$        *         C:\            Default share
IPC$      *                        Remote IPC   
share2    *         C:\Temp\share2              
Sharetest *         C:\Temp\Share    

I can remedy the issue with this:

$shares = Get-SmbShare | where {$_.Name -ne "IPC$"} | where {$_.name -ne "C$"} | where {$_.name -ne "ADMIN$"}
$shares

which gives the desired output of:

Name      ScopeName Path           Description
----      --------- ----           -----------
share2    *         C:\Temp\share2            
Sharetest *         C:\Temp\Share        

I'm looing for something that could handle a bigger exclusion list more elegantly and efficiently.

Answer 1

This is an often-confused issue when using -and and -or, or their equivalent in other programming and/or scripting languages.

If you are looking to completely exclude a set of names, you want the match to use -and - If the name is not C$ AND the name is not IPC$ AND the name is not ADMIN$, then include it in the list. Try

$shares = Get-SmbShare | where {$_.Name -ne "IPC$" -and $_.name -ne "C$" -and $_.name -ne "ADMIN$"}
$shares

-or doesn’t work because the share name C$ returns $true for the match $_.Name -ne "IPC$", and $true -or «anything» is $true.

A possibly “cleaner” way of handling this might be to create an array of exclusions, and then use -notin to check the list of objects to be selected from:

$Exclusions = "C$", "ADMIN$", "IPC$"
$Shares = Get-SMBShare | Where-Object {$_.Name -notin $Exclusions}

With this, instead of making an increasingly long and unwieldly string of comparisons joined with -and or -or, you would just add the specific exclusion to the list of exclusions, and leave the rest of the code the same.