Symbolic Links tutorial

An adult webmaster resource...

Written by Tom from Tom's Newbie Booster

What's a symbolic link?

Let's say that you have five domain names, each with a site on it. Each website has 5 pages, with a banner on every page. You want to have the same five banners on every site. You could upload all five banners to each of the site's folders - but that's hardly efficient. That would mean that your webspace then contains 5 files which are exactly the same, all taking up precious disk space. Wouldn't it be easier if they could all 'share' a central banners folder?

There is a way to use the same folder on all of those domains without keeping the images on one domain and linking to them there. That's where symbolic links come in. But they also have a lot more uses than sharing a banner. You might want to create one SSI file and allow many different webpages, on many different domains, to access that. A symbolic link is a 'shared' folder, or a 'central folder' which all other pages can access.

You can use symbolic links on all dedicated servers, and most virtual accounts too. It's a bit tricky, but once you've done it one time, it gets a lot easier after that. You only ever need to create one symbolic link from each domain in most cases - so once you've told a domain name that it is to share the central folder, it won't need doing again.

About the only requirement is that your host allows you to have Telnet / SSH access. Ask them if you are not sure if they allow this.

STEP 1) Create a folder that will be shared...

The first step is to create a folder on your server which each domain name will be able to access. The name for my central folder is /ssi/ - it's where all the images and SSI text files are stored. All of my domains have access to this one folder. If I have 1000 webpages, on many different domain names, and they all need banner1.jpg on them - I only need ONE instance of banner1.jpg on my server - in this folder. All pages can also access any adverts, my search engine script, and many more goodies from this one folder.

STEP 2) Telling a domain name where this folder is...

1) Start your SSH package. (Get Putty to do this):
http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html

2) In Host Name, type the address you log on to in FTP.

3) Click open.

4) Put in your username and press return.

5) Put in your password and press return.

6) You should be logged on to the server now.

5) The process will vary here because all servers are set up slightly different. You need to type "cd foldername" until you are in the domain name that you want to have access to the central folder. You might need to look at the path in your FTP package, or ask your host for help on this one. Let me know if you have problems at this stage. When you are in that folder, you need to then type the following:

6) Type ln -s ../ssi that's a lowercase 'L' by the way...

7) That's IT! Now log on in FTP and you'll see a folder in that domain that was not there before. You'll not be able to transfer stuff to it on that domain because that's just a folder link. You'll have to go up a level and transfer stuff to the REAL folder.

PHEW! So, what does this mean?

Well you should now be able to use that central ssi folder on each of your domain names. Yuo should be able to make SSI calls on all pages on that domain like this:

Where ssi/ is the folder that we just created.

Lemme know if you need help on any of this or have questions...

Here's a little more info:

http://www.auburn.edu/oit/software/os/unix.html#symlinks

All the best - now get SYMBOLIC LINKING!

TOM ^"^

ICQ 12616560
Email tom@tomsnewbiebooster.com