Java CLASSPATH environment

[Marvin Bellamy]

I have two questions about setting up my Java environment on 
Mandrake8.1.   BTW, I knew where to do this Slackware and Redhat. 
 Firstly, where do you initialize variables at boot?  I need to set a 
base CLASSPATH.  Second, I want to be able to run a script set a 
variable on the shell.  I know you can export a variable to a child 
process, but I don't know how to pass it back to the script's parent 
process.  Clarifying, I have several project directories, and I have a 
script to append that project's directory to the CLASSPATH.  Something like:

foreach args ("$*")
        set CLASSPATH=$CLASSPATH:$args
end

But, when the script is complete, the new CLASSPATH is "lost".  Anyone 
know how to resolve this?  I'd prefer to write the script in csh, but sh 
will do.