Powershell, how many replacements did you make?

You're right, I don't think you can squeeze anything extra out of -replace. However, you can find the number of matches using Regex.Matches(). For example

> $greeting = "Hello, Earthlings"
> $needle = "l"
> $([regex]::matches($greeting, $needle)).Length # cast explicitly to an array
3

You can then use the -replace operator which uses the same matching engine.

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After looking a little deeper, there's an overload of Replace which takes a MatchEvaluator delegate which is called each time a match is made. So, if we use that as an accumulator, it can count the number of replacements in one go.

> $count = 0
> $matchEvaluator = [System.Text.RegularExpressions.MatchEvaluator]{$count ++}
> [regex]::Replace("Hello, Earthlings","l",$matchEvaluator)
> $count
Heo, Earthings
3