Which databases are running on the machine

From Unix

ps -ef|grep [o]ra_smon|sed -e 's/.*_//'|sort|uniq

From Windows

Start,run... then:

services.msc

Look through list for services beginning with OracleService<SID> When I get the hang of bat files, I'll write a script for it.

How to see what databases have been defined (running or not)

cat /var/opt/oracle/oratab (Solaris)

cat /etc/oratab (others)