<p>Sometimes I get Oracle connection problems because I can't figure out which tnsnames.ora file my database client is using.</p>

<p>What's the best way to figure this out?  ++happy for various platform solutions.   </p>

For linux:
```
```
$ strace sqlplus -L scott/tiger@orcl 2>&1| grep -i 'open.*tnsnames.ora'
```
```
shows something like this:
```
```
open("/opt/oracle/product/10.2.0/db_1/network/admin/tnsnames.ora",O_RDONLY)=7
```
```
Changing to
```
```
$ strace sqlplus -L scott/tiger@orcl 2>&1| grep -i 'tnsnames.ora'
```
```
will show all the file paths that are failing.