[no subject]

       -X, --exclude-from FILE
              exclude files listed in FILE

So you can use the find command to generate a list of files to exclude,
and create a file from the output.  Then you can tar excluding them
like:
find / -name "*dont_tar*" > /tmp/tar_x_list && 	tar -X /tmp/tar_x_list 
-- 
-------------------------------------------------------------
 __                               .___
|  | ______________    _____    __| _/  David Kramer
|  |/ /\_  __ \__  \  /     \  / __ |   Pegasystems, Inc
|    <  |  | \// __ \|  Y Y  \/ /_/ | 
|__|_ \ |__|  (____  /__|_|  /\____ |   617-374-9600 x6330
     \/            \/      \/      \/   kramd pegasystems com
If men are from Mars and women are from Venus, there's going
to be one big fight over where to set the thermostat.