Remove 'SMTP' from 'SMTP:email@domain.com' in PowerShell using Get-AzureADUser

Question

I am using the below script to display aliases for users in O365 which I will eventually be exporting.

Get-AzureADUser |
    Select-Object @(
        @{L = "Name"; E = { $_.DisplayName}}
        @{L = "Email"; E = { $_.UserPrincipalName}}
        @{L = "Aliases"; E = { $_.ProxyAddresses -join ";"}}
    )

In the Aliases ( ProxyAddresses ) column, it displays all the aliases separated by a ; as expected but it also includes SMTP: in front of all of them.

Is there a way to remove the SMTP: from these values?

Current result : SMTP:email@domain.com;SMTP:email2@domain.com

Desired result : email@domain.com;email2@domain.com

Answer 1

Get-AzureADUser |
    Select-Object @(
        @{L = "Name"; E = { $_.DisplayName}}
        @{L = "Email"; E = { $_.UserPrincipalName}}
        @{L = "Aliases"; E = { $_.ProxyAddresses -replace '^smtp:' -join ';' }}
    )

This will replace smtp: at the beginning ( ^ ) of each proxyaddress, using PowerShell's ability to make operators automatically work on all members of an array, then join the results.

Answer 2

If you also want to lose the ".onmicrosoft.com" addresses this should work

Get-AzureADUser |
    Select-Object @(
        @{L = "Name"; E = { $_.DisplayName}}
        @{L = "Email"; E = { $_.UserPrincipalName}}
        @{L = "Aliases"; E = { 
            $proxies = $_.ProxyAddresses -replace '^smtp:'
            $proxies = $proxies | Where-Object { $_ -notlike '*.onmicrosoft.com' }
            $proxies -join '; ' }
        }
    )

Mind you, the ProxyAddresses attribute can also hold other entries like SIP:upn@domain.com or X500: /o=company/ou=External (FYDIBOHF25SPDLT)/cn=Recipients/cn=userxxx

If you also would like to exclude those, use

Get-AzureADUser |
    Select-Object @(
        @{L = "Name"; E = { $_.DisplayName}}
        @{L = "Email"; E = { $_.UserPrincipalName}}
        @{L = "Aliases"; E = { 
            $proxies = $_.ProxyAddresses
            $proxies = $proxies | Where-Object { $_ -match '^smtp:' -and $_ -notlike '*.onmicrosoft.com' }
            $proxies -replace '^smtp:' -join '; ' }
        }
    )