Perl 正则表达式 在 Bulk Rename Utility 实例

来自：Bulk Rename Utility 文档

【Bulk Rename Utility 是有效的、简洁的文件名批量替换工具，但如果想发挥它的最大功效，还是得学会正则表达式，Bulk Rename Utility 的正则表达式是 Perl Regular Expression。下面是一个实例。】

Assume you have a file called Program Files,and you wish to swap the names around (e.g. Files Program). A Regular Expression which performs this task is :

【假设我们有一个文件叫做 Program Files  ，我们想交换一下，改为 Files Program，那么Perl正则表达式应为：】

^([A-Z][a-z]*) ([A-Z][a-z]*)

Let us break this down into components:

【让我们拆解一下：】

^ This means start at the beginning of the string

【^意思是字符串开始处】

([A-Z][a-z]*) This is a single "group",which we will use later. What this says is that we want any capital letter,followed by any number of lower-case letters. The single capital letter is denoted by the [A-Z],i.e. allow a letter in the range A to Z. The lower-case letters are denoted by [a-z] in the same way,followed by an asterisk. This means we can allow any number of letters.

【([A-Z][a-z]*) 是一个独立“组”。其含义是：我们想找到所有大写字母，这些大写字母后面是小写字母。一个大写字母用 [A-Z] 代表，也就是允许A到Z中的任一大写字母。一个小写字母用 [a-z] 代表，也就是允许a到z的任一小写字母。最后的 * 星标，表示我们可以不限制满足以上条件的字母数量，可以是一个，也可以是多个。】

We then allow a single space. If I had wanted multiple spaces I would probably have typed "space asterisk",or possible ( *) to group.

【然后，我们在第一个独立组后面加一个空格。如果希望不止一个空格，那么应该用“空格+星标”，即 ( *) 表明，这里用了括号表示又一个独立组。】

We then have exactly the same again,i.e. we are denoting two words.

【再然后，我们重复了第一组的表达式，也就是说我们的目标对象是两个情况一样的单词：Program Files 。】

Notice we had two sets of brackets. Everything within each set of brackets is treated as a "grouping",and we refer to these groupings as \1,\2,\3 etc.

【注意我们有两套括号，每对括号中的内容被视为一个“分组”，这样就可以用  \1, \2, \3  来引用他们。】

So,lets say we wanted to swap around the two words in the filename. We would put:

【这样，我们的交换表达式中，匹配部分就可以这样写：】

^([A-Z][a-z]*) ([A-Z][a-z]*)

For the match string,and

【替换部分这样写：】

\2 \1

 

The above example is very precise. If we wanted to swap the first two words of a name,but keep the remaining text the same,we Could put

【上面的例子很简单，如果我们有一个文件名为：Program Files Directory ，我们只想交换前两个单词，剩下的部分保持不变，即成为：Files Program Directory，那么我们应该这样写：】

^([A-Z][a-z]*) ([A-Z][a-z]*)(.*)

\2\1\3

This says to create three groups: the first group is the first word,the second group is the second word,and the third group is everything that's left.

【这个表达式的意思是：创建三个分组，第一个是第一个单词，第二个是第二个单词，第三个是剩余的东西。】