A helpful cmdlet for converting a file containing a bunch of things of a certain type to that type, whilst handling comments and whitespace in the file easily.

Import-CommentedListFile.ps1

Function Import-CommentedListFile {
    [CmdletBinding()]
    Param (
        [Parameter(Mandatory)]
        [ValidateScript({(Test-Path -Path $_) -or (&{throw "Path does not exist: '$_'"})})]
        [string]$Path
        ,
        [Parameter()]
        [string]$Encoding = 'UTF8'
        ,
        [Parameter()]
        [Type]$Type = ([string])
    )
    Get-Content -Path $Path -Encoding $Encoding |
        ForEach-Object {$_ -replace '#.*$',''} |
        ForEach-Object {$_.Trim()} |
        Where-Object {$_} |
        ForEach-Object {
            $converted = $_ -as $Type
            if ($null -eq $converted) {
                Write-Warning "Cound not convert '$_' to '$($type.FullName)'"
            } else {
                $converted
            }
        }
}

SampleData.txt

#
# Notes on this file's format:
#   Whitespace is ignored
#   Anything following a hash on the same line is ignored / seen as a comment
#   Anything that doesn't cast to a GUID results in a warning, and is skipped
#   Any valid GUIDs are returned
#

9b0ae2db-468c-1b11-baf2-38eae400de2d    # this guid is just for demo purposes; but you can see how this may be useful?
9b0ae2db-468c-2b11-baf2-38eae400de2e
9b0ae2db-468c-3b11-baf2-38eae400de2f
9b0ae2db-468c-4b11-baf2-38eae400de2g
9b0ae2db-468c-5b11-baf2-38eae400de2h    # ooh, this one's wrong, as was the previous row... will we catch it
9b0ae2db-468c-6b11-baf2-38eae400de3a
9b0ae2db-468c-7b11-baf2-38eae400de3b
37
3879516                                 # some numbers so you can try [int] instead of [guid]
generic text
# that's all folks

SampleRunCommandsAndOutput.txt

> Import-CommentedListFile -Path '.\SampleData.txt'

9b0ae2db-468c-1b11-baf2-38eae400de2d
9b0ae2db-468c-2b11-baf2-38eae400de2e
9b0ae2db-468c-3b11-baf2-38eae400de2f
9b0ae2db-468c-4b11-baf2-38eae400de2g
9b0ae2db-468c-5b11-baf2-38eae400de2h
9b0ae2db-468c-6b11-baf2-38eae400de3a
9b0ae2db-468c-7b11-baf2-38eae400de3b
37
3879516
generic text

> Import-CommentedListFile -Path '.\SampleData.txt' -Type ([guid])              

WARNING: Cound not convert '9b0ae2db-468c-4b11-baf2-38eae400de2g' to 'System.Guid'
WARNING: Cound not convert '9b0ae2db-468c-5b11-baf2-38eae400de2h' to 'System.Guid'
WARNING: Cound not convert '37' to 'System.Guid'
WARNING: Cound not convert '3879516' to 'System.Guid'
WARNING: Cound not convert 'generic text' to 'System.Guid'
Guid
----
9b0ae2db-468c-1b11-baf2-38eae400de2d  
9b0ae2db-468c-2b11-baf2-38eae400de2e  
9b0ae2db-468c-3b11-baf2-38eae400de2f  
9b0ae2db-468c-6b11-baf2-38eae400de3a  
9b0ae2db-468c-7b11-baf2-38eae400de3b

> Import-CommentedListFile -Path '.\SampleData.txt' -Type ([int])

WARNING: Cound not convert '9b0ae2db-468c-1b11-baf2-38eae400de2d' to 'System.Int32'
WARNING: Cound not convert '9b0ae2db-468c-2b11-baf2-38eae400de2e' to 'System.Int32'
WARNING: Cound not convert '9b0ae2db-468c-3b11-baf2-38eae400de2f' to 'System.Int32'
WARNING: Cound not convert '9b0ae2db-468c-4b11-baf2-38eae400de2g' to 'System.Int32'
WARNING: Cound not convert '9b0ae2db-468c-5b11-baf2-38eae400de2h' to 'System.Int32'
WARNING: Cound not convert '9b0ae2db-468c-6b11-baf2-38eae400de3a' to 'System.Int32'
WARNING: Cound not convert '9b0ae2db-468c-7b11-baf2-38eae400de3b' to 'System.Int32'
37
3879516
WARNING: Cound not convert 'generic text' to 'System.Int32'
>