Answer:
4. Command line interface (CLI)
Explanation:
An operating system is a system software pre-installed on a computing device to manage or control software application, computer hardware and user processes.
This ultimately implies that, an operating system acts as an interface or intermediary between the computer end user and the hardware portion of the computer system (computer hardware) in the processing and execution of instructions.
Some examples of an operating system on computers are QNX, Linux, OpenVMS, MacOS, Microsoft windows, IBM, Solaris, VM etc.
A Command line interface (CLI) refers to a text-based user interface that allow users to operate a software application or program, as well as manage and execute operating system functions by typing standard line of commands into the text-based user interface with a real-time response.
Basically, the CLI is solely text-based and as such requires a thorough knowledge and understanding of global commands, as well as administrative privileges in some cases.
<em>Hence, the operating system function which has a steeper learning curve (more difficult to learn) and can potentially break the system without careful use of its operations is the Command line interface (CLI). </em>
