Outputting PowerShell data to a string - string

Question

This is really PowerShell 101, I realise, but I'm stuck.
I'm trying to iterate through a folder tree, getting each subfolder name and a count of files. No problems there.
The new requirement is to get the ACLs on each subfolder as well. All of this data needs to be output as a CSV file, with a line consisting of each folder name, the file count, and the ACLs in a single string in one field of the CSV (I was going to delimit them with semicolons).
I am open to exporting to XML if the data can be viewed in Excel.
The part where I'm stuck is getting the ACL information into a single string for the CSV.
Get-ACL on each directory shows the data as follows (I'm doing a Select to just get the IdentityReference and FileSystemRights, which is all we're interested in):
IdentityReference FileSystemRights
----------------- ----------------
BUILTIN\Users ReadAndExecute, Synchronize
BUILTIN\Users AppendData
BUILTIN\Users CreateFiles
I would like the output file formatted with one line per subdirectory, similar to
#filecount,folder,perms
51,C:\temp,BUILTIN\Users:ReadAndExecute,Synchronize;BUILTIN\Users:AppendData...
I however can't get any kind of join working to have it presented in this way. I don't care about what combination of delimiters are used (again, must be readable in Excel).
The script, such as it is, is as follows. The output file has its line of data appended with each directory it traverses. I'm sure this isn't very efficient, but I don't want the process consuming all the server memory either. The bits I can't figure out are prepended with ###.
(Get-ChildItem C:\temp -recurse | Where-Object {$_.PSIsContainer -eq $True}) | foreach {
$a = ($_.GetFiles().Count)
$f = $_.FullName
$p = (get-acl $_.FullName).Access | select-object identityreference,filesystemrights
### do something with $p?
Out-File -FilePath c:\outfile.csv -Append -InputObject $a`,$f`,###$p?
}

Answer 1

Since you want all ACEs of a folder mangled into a single line you need something like this:
Get-ChildItem 'C:\temp' -Recurse | ? { $_.PSIsContainer } | % {
# build a list of "trustee:permissions" pairs
$perms = (Get-Acl $_.FullName).Access | % {
"{0}:{1}" -f $_.IdentityReference, $_.FileSystemRights
}
New-Object -Type PSObject -Property #{
'Filecount' = $_.GetFiles().Count
'Folder' = $_.FullName
'Permissions' = $perms -join ';' # join the list to a single string
}
} | Export-Csv 'c:\outfile.csv' -NoType
Repeated appending inside a loop usually guarantees poor performance, so it should be avoided whenever possible. The outer loop creates a list of custom objects, which can then be exported via Export-Csv in a single go.