Using a text file to loop through PowerShell command - powershell

Question

I have a text file test.txt which contains a list of OUs where I need to count the number of users found within each OU.
test.txt:
"ou=MyOU1,dc=Mydomain,dc=net"
"ou=MyOU2,dc=Mydomain,dc=net"
"ou=MyOU3,dc=Mydomain,dc=net"
I am passing this to command in PowerShell:
Get-Content .\test.txt | Out-String | ForEach-Object {
(Get-ADUser -Filter * -SearchBase "$_").Count
}
I'm getting the following error:
Get-ADUser : The supplied distinguishedName must belong to one of the
following partition(s): 'DC=Mydomain,DC=net ,
CN=Configuration,DC=Mydomain,DC=net ,
CN=Schema,CN=Configuration,DC=Mydomain,DC=net ,
DC=ForestDnsZones,DC=Mydomain,DC=net ,
DC=DomainDnsZones,DC=Mydomain,DC=net'.
At line:1 char:62
+ ... ing) | ForEach-Object {(Get-ADUser -Filter * -SearchBase "$_").Count}
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidArgument: (:) [Get-ADUser], ArgumentException
+ FullyQualifiedErrorId : ActiveDirectoryCmdlet:System.ArgumentException,Microsoft.ActiveDirectory.Management.Commands.GetADUser
However, when I run the OU individually, it works.
PS> (Get-ADUser -Filter * -SearchBase "ou=MyOU1,dc=Mydomain,dc=net").Count
10782

Answer 1

Note: Use of Out-String is not only unnecessary in your code, but actually creates a single output string, which causes your command to malfunction, because ForEach-Object is then only called once, with a multi-line string.
Get-Content by itself sends the lines of a text file individually through the pipeline, which is what you want:
Get-Content .\test.txt | foreach-object {
(get-aduser -filter * -searchbase $_).count
}
Note that $_ already is a string, so you needn't enclose it in "...".
Aside from that, if the lines in your file really contain "..."-enclosed strings, as your sample input suggests (probably not, because the error message does not reflect them), and you cannot fix the file itself, you'd have to remove these double quotes, as they otherwise become part of the string that is passed to -SearchBase:
Get-Content .\test.txt | foreach-object {
(get-aduser -filter * -searchbase ($_ -replace '"')).count
}