hexo 2.8.3 to 3.1.1 tag plugin migrate

hexo-migrate.js

/*
  $ npm install mkdirp --save
  $ node hexo-migrate.js _post/
  $ cd file_migrate/_post
 */
var fs = require("fs");
var path = require("path");
var mkdirp = require("mkdirp");

function file_migrate(file_path) {
    fs.readFile(file_path, function(err, buf_data) {
        var data = buf_data.toString();
        data = data.replace(/{% math-block/g, '{% math_block');
        data = data.replace(/{% endmath-block/g, '{% endmath_block');
        data = data.replace(/{% rawblock/g, '{% raw');
        data = data.replace(/{% endrawblock/g, '{% endraw');
        var start_pos = 0;
        while (true) {
            var st_str = '{% math ', args = '';
            var pos = data.indexOf(st_str, start_pos);
            if (pos == -1)  break;
            for (var i = pos + st_str.length; i < data.length; i++) {
                if (data[i] == '%' && data[i+1] == '}') {
                    var tmp = data.substring(0, pos-1) + '{% math %}' + args + '{% endmath %}';
                    start_pos = tmp.length;
                    data = tmp + data.substring(i+2);
                    break;
                }
                args = args + data[i];
            }
        }
        var store_path = path.join('file_migrate', file_path);
        mkdirp(path.dirname(store_path), function (err) {
            if (err) return 0;       
            fs.writeFile(store_path, data, function(err) {
                if (err) {
                    console.log(err);
                    return 0;
                }
                console.log('success : ' + file_path);
            });
        });
    });
}

function read_dir(dir) {
    fs.readdir(dir, function(err, files) {
        if (err)	return 0;
        // Print folder name
        files.forEach(function(file) {
            file_full_path = path.join(dir, file);
            (function(file_full_path) {
                // Get file stat
                fs.stat(file_full_path, function(err, stats) {
                    if (err)    return 0;
                    if (stats.isDirectory())
                        read_dir(file_full_path);
                    if (!stats.isDirectory()) {
                        file_migrate(file_full_path);
                        // console.log("file_full_path="+file_full_path);
                    }
                });
            })(file_full_path);
        });
    });
}

read_dir(process.argv[2]);