File Formats on the Web

As you go looking for research materials on the web, you'll find documents available in a range of formats. Here are some of the more common types you'll find, and what to do with them.

• PDF Files: These typically have a .pdf extension. View with Acrobat Reader. Depending on how your browser is set up, rather than clicking on the file to open it in the browser, it may be better to right-click, save the file locally, then open it from there: in some setups, when you open a PDF file directly in the browser, you may not be offered an option to save a copy.

• PostScript Files: These typically have a .ps extension. Under Windows, view with GSView, which you'll have to install first: search the web to find where to get it from. Unix systems should already have this, or something functionally similar, installed. An alternative is to convert the PS file to a PDF file. This is not a bad idea for other reasons in any case: PDF files are smaller and more universally readable. To convert a PS file to PDF, move it to a local Unix system and run the distill program as follows:

  distill file

  This will create a PDF file with the same name but with the extension .pdf. You can then view this as described above.

• Gzipped Files: Occasionally you'll find files on the web which have been compressed to save space and to speed up download times. There are lots of different compression schemes but a common one used on Unix systems is gzip; gzipped files have the extension .gz. You can uncompress these using WinZip under Windows, or using gunzip under Unix. Note that some browser setups may actually do the decompression as part of downloading.

• Tar Files: These are Unix 'tape archives': the tar format was originally developed for storing data on tapes but is now widely used as a way of packaging up a number of related files into one file for easy transport. To untar a file under Unix, the simplest approach is to say <

  tar -xvf file

  This will unpack the file in the current directory. Check the Unix man page for tar to see the many other things you can do with tar. On the other hand, if you're on a Windows machine, WinZip knows how to handle tar files. You'll often find that tar files are also gzipped, so you get a file with the extension .tar.gz. WinZip handles these very comfortably.

[Did you find this page useful? Did it miss out something on the topic you thought was important? Is some part of it wrong? Mail me and let me know.]

[Home|Teaching|Research|Publications|Professional Activities|Resources]

Please send comments or queries about this web site to Robert.Dale@mq.edu.au
Last Modified: 10 April 2002