Setting up system variables:

For bash shell:
export CLASSPATH=$CLASSPATH:/java/classes:/home/tchin/myclasses

For tcsh or csh:
set CLASSPATH = ($CLASSPATH /java/classes /home/tchin/myclasses)

I always get confused about these two shells
echo $SHELL will tell the shell on which we are working

Also concept is this:
These are 2 forms of setting up the enviornment variable settings.

sh and ksh:
--------
TERM=sun
export TERM
these 2 command set any environment variable here.

csh:
----
in c shell setenv accomplish the task of those 2 commands alone.
so it depends on your shell, which shell u are using u have to use one of these commands.