Script example for post https://powershell.org/forums/topic/extract-information-from-log-file-using-powershell/

powershell-forum-extract-information-from-log-file-using-powershell-reply-01.ps1

$logFileContent = Get-Content -Path C:\My\Forum\mail.log -Raw

$regExMatches = [regex]::Matches($logFileContent, '(?<timestamp>[0-9/: ]+)\tUser (?<email>[a-z0-9@.]+) logged on')
$items = $regExMatches | ForEach-Object {
    [PSCustomObject]@{
        timestamp = [DateTime]$_.Groups['timestamp'].value
        email = $_.Groups['email'].Value
    }
}
$items | Group-Object -Property email | Select-Object -Property Name, Count | Sort-Object -Property Count -Descending