What's a URL?

(Here's a short tutorial I wrote about URL's for my office.)

A "URL" is a Uniform Resource Locator (NOT a Universal Resource Locator). It is similar to a file specification. For example, say that a file is a Word Perfect document on the C: drive, in the sub-directory \SURVEY\TEXAS, and the filename is THISYEAR.DAT. The file specification would be "C:\SURVEY\TEXAS\THISYEAR.DAT". Unlike a file specification, a URL includes the method for accessing file, and the computer on which it is located, in addition to the disk, subdirectories, and filename. So,

http://www.clark.net/pub/teallen/cads.html
http:	//www.clark.net	/pub/teallen	/cads.html
Access via hypertext protocol.	It's on a computer named www.clark.net.	In directory /pub/teallen.	The filename is cads.html.

URL's can be abbreviated somewhat. Specifying everything except the filename (e.g. "http://www.clark.net/pub/teallen/" causes a default filename to be added to the end of the URL. This is usually "index.html". Specifying ONLY a filename (without the access method, computer name (IP address), or directories) results in a relative URL: The computer assumes that all of the missing details are the same as those of the document from which you linked. In this document, a URL like "next.html" would be assumed to mean "http://gri.gallaudet.edu/Tutorials/next.html". There are some other forms of relative URL's, but I won't discuss them here.

It's also possible to place jump-points within a document. In order to reach these jump-points, a pound sign (a.k.a. number sign) followed by the name of the jump-point is appended to the URL. For example, the paragraph about abbreviated URL's above might contain a jump-point named abbrev. In order to go to this point, the full URL would be:

There are a few other things you need to know to make specific examples work, but this is the general gist. If you are provided with the URL, you can then tell Lynx or Mosaic to "point" directly to a document to retrieve it. Assuming I have set up Lynx for you, at the $ prompt, you would type:

(Type it in with the exact case. Don't capitalize, unless it's shown in caps. VAX/VMS users: Be sure to surround the URL with quotes as shown above.)