This is the case of an incident that occurred to me after installing a new Oracle Database.
I installed a new database and the SQLPLUS was working normally for a couple days.
Suddenly one day, I tried to run SQLPLUS but I got the usual error Command Not Found.
At first I checked the Oracle Home to be set with:
. oraenv
echo ORACLE_HOME
Everything was set properly but the error still occurred.
Then I checked the Path (Environment Variables) to see that the Oracle_Home/bin path is included there and as expected it was properly too.
Since I could not run the SQLPLUS via command line, I decided to run it manually from the regarding path in Oracle Home.
When I searched the directory, I found out that the SQLPLUS.exe and some other files of SQLPLUS functionality were missing.
I researched it, and what I found out was that my Avast Antivirus for some reason thought it was a malicious software, so it had removed it from the directory.
After that, I downloaded and restored manually the whole SQLPLUS folder so that it would contain all the necessary files and also added an exception to my antivirus to not include any Oracle directories anymore.
Written by Nikos Minaidis
15/12/2021
Nikos Minaidis 