using System;
using System.Linq;
using System.Text.RegularExpressions;
public class Test
{
public static void Main()
{
var text = @"blah blah blah
some stuff to be numbered
more stuff to number";
var index = 1;
var result = Regex.Replace(text, "^",
(Match m) => (index++).ToString() + " ",
RegexOptions.Multiline);
Console.WriteLine(result);
}
}
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