Comparing multiple email address using powershell match

Question

I have a CSV file of 2000 email addresses. I am using PowerShell to check if the user is active in AD. Another developer wrote a PowerShell script for me to do this but he only used the main domain for the email format to match, he didn't add the subdomian that it could have. Some of our email addresses have a 3 part email address after the @ symbol.

For example, his code:

foreach ($user in $users) {
    Write-Host $user.email
    if ($user.email -match "\@mycompany\.com$") {
        $status = "NOT FOUND"
        # loop through possible AD domains until there is a hit
        foreach ($domain in "na","au","eu","as") {
            if ($status -eq "NOT FOUND") {
                Write-Host "  $($domain)" -NoNewline
                $status = Get-UserFromEmail -EMail $user.email -ADDomain $domain
                Write-Host $status
            }
            else {
                break
            }
        }
        Write-Host
        Add-Content -Path $outcsv -Value "$($user.email),$($user.type),`"$($status)`""
    }
    else {
        Add-Content -Path $outcsv -Value "$($user.email),$($user.type),NOT MYCOMPANY"
    }

What I need to be able to do is get the match to check if it is a two or three part email address. @consultant.mycompany.com or @mycompany.com.

Any insight for this PowerShell newbie would be appreciated.

Answer 1

here is one way to test for membership in more than one email domain. all of the domains are all in the same example.com , but they could easily be in testing.com or wizbang.org .

this demos the idea, i presume you can insert it into your script as needed. [ grin ]

what it does...

• builds a list of email addresses to test
  you will get that from your source... just be sure they are plain strings, not a string inside a property of an object.
• builds a domain list
• uses the built in regex escape method to escape things like dots as they are needed
• adds a $ to the end of each escaped string to anchor the pattern to the end of the email address
• uses the escaped strings to build a regex OR of that list
• iterates thru the email address list and gets the ones that match one of the domain list items
• saves the matches to a $Var
• displays the content of that $Var on screen

the code...

$EmailList = @(
    'ABravo@example.com'
    'BCharlie@more.example.com'
    'CDelta@example.com'
    'DEcho@zigzag.papers.com'
    'EFoxtrot@even.more.example.com'
    )

$DomainList = @(
    '@example.com'
    '@more.example.com'
    '@even.more.example.com'
    )
$Regex_DL = $DomainList.ForEach({
    [regex]::Escape($_) + '$'
    }) -join '|'

$ValidEmailAddressList = $EmailList -match $Regex_DL

$ValidEmailAddressList

output...

ABravo@example.com
BCharlie@more.example.com
CDelta@example.com
EFoxtrot@even.more.example.com

Answer 2

You can always use the -or operator to chain multiple expressions inside the if condition:

if ($user.email -match "\@mycompany\.com$" -or $user.email -match '@consultant\.mycompany\.com$'){
  # ...
}

Alternatively, you can construct a regex pattern that'll match both:

if($user.email -match '@(?:consultant\.)?mycompany\.com$'){
  # ...
}

---

If you're ever unsure about how to escape a literal string in a reguar expression, use [regex]::Escape() :

PS C:\> [regex]::Escape('@consultant.mycompany.com')
@consultant\.mycompany\.com