To prevent malware from accessing your Mac, Apple enables GateKeeper by default, only allowing you to install and run applications from the App Store or identified Developers (Adobe, Microsoft, etc.).
For example, with GateKeeper enabled when you run
sqlplus the first time, it will show you the following message.
To enable it you must go to the System Preferences and click on Always Allow.
As developers, this can become a problem when using terminal applications, then to be able to install and run all kinds of applications, we need to disable GateKeeper.
Important: Only disables GateKeeper temporarily during a project or work session, not permanently.
In terminal run the following command.
sudo spctl --master-disable
All options are displayed "App Store", "App Store and identified developers" and "Any Site".
Select the Any Site option.
That's it, now you can install and run any application. 😃
If you want to enable GateKeeper back, I will show you how to do it in this link.