Note: You can copy the setenv.sh (see Attachments) to $CATALINA_BASE/bin path or create your own setenv.sh that tomcat.sh script will use to source Tomcat and Java environment variables.
You can also use the sample tomcat5.sh or tomcat7.sh template scripts in commons-daemon-1.0.x-native-src/unix/sample folder or create your own script to run Tomcat.
For more information, see http://tomcat.apache.org/tomcat-6.0-doc/setup.html#Unix_daemon.