How can I know an installed tomcat’s version

http://www.velocityreviews.com/forums/t130752-how-do-i-find-tomcat-version-thats-already-installed.html

You should be able to find this in the log called ‘catalina.out’.

Alternatively, you can go right to the source; open

$TOMCAT_HOME/server/lib/catalina.jar in a tool capable of handling zip

or jar files, and read the file called

org/apache/catalina/util/ServerInfo.properties.

That last bit is not guaranteed to work across multiple versions,

though.