Unix operating system features

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The UNIX kernel runs on specific hardware and effectively interacts with the hardware. Unix operating system layers picture(3) Also, as a device manager, it provides valuable functions for processes that need access to peripheral devices connected to the computer. The kernel will control these devices through their associated drivers. The kernel also manages memory. Processes are running programs that are started by their owner, which can be the user or the system. The system must provide the necessary memory access for all processes. Some processes require a lot of memory to run. Techniques such as paging, swapping and virtual memory are used in order to optimally use the main memory and allocate a sufficient amount of memory to each process.


Layer 3: shell or shell Shell is an interpreter that interprets the commands entered by the Uruguay Phone Number List user in the terminal and calls the desired program with just a simple command. It also saves a history of the list of commands you have entered. If you need to repeat a command, you can simply use the up and down arrow keys to scroll through the list of entered commands. Also, with the history command, the list of previous commands will be visible. Shell supports various commands such as cat, mv, grep, id, wc, etc. The following image shows shell types in Unix operating system: picture (4) Bourne Shell : This shell is simply called shell and is the first default shell in Unix systems. The Bourne Shell is still the most widely used shell on Unix systems.




C Shell : Another popular shell that is available by default in Unix systems. C Shell was developed by the University of California at Berkeley and has fixed some of the shortcomings of the Bourne Shell. Korn Shell : This shell was created by David Korn to fix user interaction problems in Bourne Shell and scripting errors in C shell. As the outermost layer, this layer is responsible for executing external applications. Unix distributions usually come standard with several useful utilities. Among these programs, we can mention emacs editor, StarOffice, xv image viewer, g++ compiler, etc.