OK. I'd certainly suggest that from a management and configuration point of view you should at least understand how to navigate the file system and edit files.
Regarding learning resources, just Google it. I found this which might make a good start around the filesystem: http://www.ee.surrey.ac.uk/Teaching/Unix/ and this for editing using vi: http://acms.ucsd.edu/info/vi_tutorial.html
So, for what you want to do, starting from the Advanced Shell;
*cd /config Move to config directory
*ls List files
*vi 'filename' Edit a file
*Enter /500 to search for the string 500
*Change the 5 to a 4 (put cursor under 5, hit delete, press i, enter 4, press ESC)
*Enter / to search for the next match
*Continue till you've done the whole file
*Enter :w:q to save and quit
*Repeat with next file etc.