Setting JVM options for Tomcat question

[Rustican]

I'm trying to set the maximum heap size that the JVM is able to use on my Tomcat application. I've got it running on my Linux box and am trying to follow the instructions found here:

http://tomcat.apache.org/tomcat-4.1-doc/security-manager-howto.html

It says for Linux: place the Java options into the CATALINA_OPTS environment variable. For example: "-server -Xmx400m".

Where do i find the the CATALINA_OPTS environment variable and how do i set it? Do i just add in the line in the the startup.sh or the catilina.sh?

EXECUTABLE=catalina.sh -server -Xmx400m