How do I find out which of the many files is actually being used?

For example, you may see this error when logging on the datamover in bootstrap mode (for example, using SYSADM).

/etc /usr etc) and: If $TNS_ADMIN is not set, then the should be in $ORACLE_HOME/network/admin/.

You can find more explanations on in Net Services Reference book.

99% of the time, this error turns out to be something that I overlooked and I could have resolved the error in a few minutes rather than wasting hours.

As a result, I decided to document it here so everyone can benefit.