Relinking a Multi-Page Web Document

When you need some help getting your web pages back in order, have the computer do it for you.

There is something magical about writing a web-based document that just doesn't exist with a regular linear document. Something about getting all those links just right and in the right sequence makes a web document come alive. Of course, getting the links just right can be a big job, especially in a document with many pages. I found that out when I tackled my first multi-page document.

I had been writing HTML for several months when an opportunity came to make a presentation at our local Internet Special Interest Group (part of a larger PC users group). At that time, only a few of us were “on the Net”, but many people were interested in what the Internet—and more specifically—what the Web could do for them. I volunteered to give a talk on the basics of HTML and putting together your own web page.

The group met in the library of a local university, and we had a live Internet connection tied into an overhead projector in the room. I decided it would be neat to write a presentation about HTML in HTML. Each web page would be a single slide in the presentation. Links between pages would allow me to move forward (and backward) as the talk progressed.

So I put together about 15 pages of slides and linked them so each page had a next link to the next page and a prev link to the previous page. I put these links at the top and bottom of each page, so there were four links on every page (actually, I had links to the table of contents too, but let's ignore those for the moment). Figure 1 shows how consecutive pages are linked.

The talk went well, but I saw several places where I could improve the talk. When I started adding pages to the document, I made a very important discovery: inserting pages was a big pain. If I wanted to insert a new page between existing pages A and B. I had to update the NEXT links in page A, update the PREV links in page B, and update both the NEXT and PREV links in the new page. And because I had links at the top and bottom of the pages, there were twice as many links to update. Figure 2 shows the revised links.

Automation to the Rescue

After struggling with manual updates to the pages, I decided there had to be a better way. The relink Perl script was a result of that frustration.

Using relink is simple. First you need a file (called links) containing a list of pages in the order they are to be visited. Omit the “.html” portion of the page name in the links file, relink assumes the files end with that extension.

For example, consider the following (very abbreviated) version of my original HTML presentation. I start with an introduction (intro.html), have a page about anchors (anchor.html) and finish with a conclusion (conclude.html). The links file would contain:

   # Pages for a simple presentation
   intro
   anchor
   conclude

Each HTML page contains a set of links to its next and previous page. For example, the anchor.html file contains the following links at the top and bottom of the page.

   <a href="conclude.html">
      <img src="icons/next.gif" alt="NEXT">
   </a>
   <a href="intro.html">
      <img src="icons/prev.gif" alt="PREV">
   </a>
After reviewing my short document, I feel that I really should mention URLs and how they work before delving into anchors. So I write a new page called url.html and wish to add it to my document. I simply edit the links file to contain:
   # Pages for an updated, but still
   # simple presentation
   intro
   url
   anchor
   conclude
After running relink with the new page order, the links in the anchor page will now look like:
   <a href="conclude.html">
      <img src="icons/next.gif" alt="NEXT">
   </a>
   <a href="url.html">
      <img src="icons/prev.gif" alt="PREV">
   </a>
Notice the previous link now points to the page about URLs, rather than the introduction. The links in the other pages are updated in a consistent manner to support the new page order. Pages can be added, deleted, or simply rearranged just by editing the links file and specifying the new order.

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