问用于捕获=和之间的单词的RegEx；

EN

(.+=)?(.+?);

(.+=)?(.+?)(?:;.+)

using System;
using System.Text.RegularExpressions;

public class Example
{
    public static void Main()
    {
        string pattern = @"(.+=)?(.+?);";
        string input = @"word1=word2;word3
word2;word3";
        RegexOptions options = RegexOptions.Multiline;

        foreach (Match m in Regex.Matches(input, pattern, options))
        {
            Console.WriteLine("'{0}' found at index {1}.", m.Value, m.Index);
        }
    }
}

using System;
using System.Text.RegularExpressions;

public class Example
{
    public static void Main()
    {
        string pattern = @"(.+=)?(.+?)(?:;.+)";
        string substitution = @"$2";
        string input = @"word1=word2;word3
word2;word3";
        RegexOptions options = RegexOptions.Multiline;

        Regex regex = new Regex(pattern, options);
        string result = regex.Replace(input, substitution);
    }
}