Answer

This describes a quick process of updating Drupal core.

1. Make back-ups.

2. Download latest version of Drupal onto Unix server

wget http://ftp.drupal.org/files/projects/drupal-6.15.tar.gz

3. Extract the tar file

tar -xvf

This will create a new directory (e.g. drupal-6.15) containing the Drupal files.

4. Copy the Drupal 'sites' directory from old site to the new site

cp -Rv shop/sites drupal-6.15/sites

5. Move old site directory to an underscore version.

mv shop _shop

6. Move new site directory to required name.

mv drupal-6.15 shop

7. Change owership of files as required

chown -Rv mreid.mreid shop

8. Change permissions on 'files' directory and all sub directories and content

chmod -Rv 777 sites/default/files

9. Run Drupal update from browser.

http://beamish/drupal/shop/update.php

The update will report on success and any problems that may need attention.