What happens when the dump file and log file names are the same during expdp?

Though it was a silly mistake, I felt discussing the funny part here.

Few days ago, I was doing an export (datapump) and come across the following error:

Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
ORA-39001: invalid argument value
ORA-39000: bad dump file specification
ORA-31641: unable to create dump file "/tmp_backup/dpump/text.dmp"
ORA-27038: created file already exists
Additional information: 1

For the first few minutes, I was wondering what went wrong and started checking all the arguments that were passed with expdp command as the error message suggested  'invalid argument value'. After confirming everything is fine with the command and then started looking at the subsequent error messages.  My second thought was, the file could be already exits. I deleted the file and run the expdp command which result in same error.
Any guesses what could be wrong here? Well, no prize for guessing. It was a silly mistake that I had committed. I had given the similar file name to the dumpfile and logfile arguments in the expdp command.

Sometime we may overlook the basic problems.

Happy reading,

Jaffar