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Here’s part 12 of the ongoing serialization of Refactoring HTML, also available from Amazon and Safari.

Manually inspecting and changing each file on even a small site is tedious and often cost-prohibitive. It is much more effective to let the computer do the work by searching for mistakes and, when possible, automatically fixing them. A number of tools support this, including command-line tools such as grep, egrep, and sed; text editors such as jEdit, BBEdit, TextPad, and PSPad; and programming languages such as Java, Perl, and PHP. All these tools provide a specialized search syntax known as regular expressions. Although there are small differences from one tool to the next, the basic regular expression syntax is much the same.

For purposes of illustration, I’m going to use the jEdit text editor as my search and replace tool in this section. I chose it because it provides pretty much all the features you need, it has a reasonable GUI, it’s open source, and it’s written in Java, so it runs on essentially any platform you’re likely to want. You can download a copy from http://jedit.org/.

However, the techniques I’m showing here are by no means limited to that one editor. In my work, I normally use BBEdit instead because it has a slightly nicer interface. However, it’s payware and only runs on the Mac. There are numerous other choices. If you prefer a different program, by all means use it. What you’ll need are:

• Full regular expression search and replace
• The ability to recursively search a directory
• The ability to filter the files you search
• A tool that shows you what it has changed, but does not require you to manually approve each change
• Automatic recognition of different character encodings and line-ending conventions

Any tool that meets these criteria should be sufficient.