Linux based Tomcat6 should have /etc/tomcat6/tomcat6.conf
# System-wide configuration file for tomcat6 services
# This will be sourced by tomcat6 and any secondary service
# Values will be overridden by service-specific configuration
# files in /etc/sysconfig
#
# Use this one to change default values for all services
# Change the service specific ones to affect only one service
# (see, for instance, /etc/sysconfig/tomcat6)
#
# Where your java installation lives
#JAVA_HOME="/usr/lib/jvm/java-1.5.0"
# Where your tomcat installation lives
CATALINA_BASE="/usr/share/tomcat6"
...