Tired of having to retype every damn line into sqlplus when you make a mistake? Use uniread for command history.
If you've upgraded your oracle server from 8.1.6 to 8.1.7 and now you're getting errors like:
Error accessing package DBMS_APPLICATION_INFO
ORA-06553: PLS-707: unsupported construct or internal error 
go into your $ORACLE_HOME/rdbms/admin directory and run the standard.sql script from within sqlplus as the SYS user.
If you're getting the following error messages:
undefined reference to `oracle::occi::Environment::createEnvironment(oracle::occi::Environment::Mode, void*, void* (*)(void*, unsigned), void* (*)(void*, void*, unsigned), void (*)(void*, void*))'
undefined reference to `oracle::occi::Environment::terminateEnvironment(oracle::occi::Environment*)'
then you're probably running oracle9i on redhat 8.0. to solve this, download and install the following rpm's from this redhat link:
and compile with g++296 instead of g++. sure you'll be stuck with g++-2.96, but at least it will compile and run.