encoding declarations

For Python

If a comment in the first or second line of the Python script matches the regular expression coding[=:]s*([-w.]+), this comment is processed as an encoding declaration; the first group of this expression names the encoding of the source code file. The encoding declaration must appear on a line of its own. If it is the second line, the first line must also be a comment-only line. The recommended forms of an encoding expression are

# -*- coding: <encoding-name> -*-

For Ruby

参考

Ruby 文件中如果未指定编码，在执行过程会出现报错：

#!/usr/bin/ruby -w

puts "你好，世界！";

以上程序执行输出结果为：

invalid multibyte char (US-ASCII) 

以上出错信息显示了 Ruby 使用用 ASCII 编码来读源码，中文会出现乱码，解决方法为只要在文件开头加入 # -- coding: UTF-8 --（EMAC写法） 或者 #coding=utf-8 就行了。

#!/usr/bin/ruby -w
# -*- coding: UTF-8 -*-

 puts "你好，世界！";