How exactly does Tomcat run out of CATALINA_HOME and CATALINA_BASE - tomcat6

Question

I'm having trouble finding documentation regarding this. After some googling I find that bin, conf,logs, temp, webapps, work are directories that should exist in CATALINA_BASE.
temp, logs, webapps, bin and work I don't have any trouble understanding.
bin I suppose is just another bin folder, if for some reason both CATALINA_HOME and CATALINA_BASE are in PATH, then scripts in both folders will be available for execution.
But how about conf? Will the content of CATALINA_HOME/conf be totally ignored if CATALINA_BASE is set? Suppose I only would need to customize only a few config files pr. CATALINA_BASE, would I still need to keep a complete set of config files in CATALINA_BASE/conf, or could the standard config files in CATALINA_HOME/conf be shared?
And ditto for CATALINA_BASE/lib ... would this work as a "global" lib folder pr. instance?

Answer 1

You can find the answer in the Tomcat documentation:
http://tomcat.apache.org/tomcat-6.0-doc/RUNNING.txt
Advanced Configuration - Multiple Tomcat Instances
In many circumstances, it is desirable to have a single copy of a
Tomcat binary distribution shared among multiple users on the same
server. To make this possible, you can set the $CATALINA_BASE
environment variable to the directory that contains the files for your
'personal' Tomcat instance.
When you use $CATALINA_BASE, Tomcat will calculate all relative
references for files in the following directories based on the value
of $CATALINA_BASE instead of $CATALINA_HOME:
bin - Only setenv.sh (*nix), setenv.bat (windows) and tomcat-juli.jar
conf - Server configuration files (including server.xml)
logs - Log and output files
webapps - Automatically loaded web applications
work - Temporary working directories for web applications
temp - Directory used by the JVM for temporary files (java.io.tmpdir)
Note that by default Tomcat will first try to load classes and JARs
from $CATALINA_BASE/lib and then $CATALINA_HOME/lib. You can place
instance specific JARs and classes (e.g. JDBC drivers) in
$CATALINA_BASE/lib whilst keeping the standard Tomcat JARs in
$CATALINA_HOME/lib.
If you do not set $CATALINA_BASE, $CATALINA_BASE will default to the
same value as $CATALINA_HOME, which means that the same directory is
used for all relative path resolutions.