Using that RegularExpression MatchEvaluator in PowerShell

Measure-SubstringCount.ps1

function Measure-SubStringCount {
    <#
        .SYNOPSIS
            Counts occurrences of a regex pattern in the input, shows them with -Verbose
        .DESCRIPTION
            Written as an example of how the Regex MatchEvalutor can be (ab)used for good.
    #>
    [CmdletBinding()]
    param(
        [string]$Pattern,
        [Parameter(ValueFromPipeline)]$InputObject
    )
    begin {
        $script:i = 0 
    }
    process {
        Write-Verbose "`e[39m$([regex]::Replace($InputObject, $Pattern, { $script:i++; "`e[91m${script:i}`e[39m" }))"
    }
    end {
        $script:i 
    }
}