What is UNIX operating system? UNIX is a family of operating systems initially developed by AT&T in the late 1960s at Bell Labs research centre. It contains multiuser and multitasking operating systems. This is a complete Operating System that has a kernel, shells, and programs as a part of it. This article will cover detailed information related to UNIX Operating System along with its features, advantages, and disadvantages. 

What is UNIX operating system?

UNIX is one of the oldest computer Operating Systems that was created around 1970. It is a multitaskingmultiuser Operating system primarily developed for servers, mainframes, and workstations. Some UNIX systems have Graphical User Interface for the novices to operate efficiently. However, you will still need in-depth knowledge of command-line utilities to accomplish a large number of tasks in UNIX.

The majority of today's operating systems can be grouped into two categories. Aside from Microsoft Windows NT-based operating systems, nearly every other operating system is a 'descendant' of Unix.

Architecture of UNIX


A kernel is the fundamental component of an operating system that manages all machine-related tasks. The kernel is the component that handles application execution, resource management, event timing, and everything else that the operating system does as part of its job.

The kernel is also in charge of keeping track of the various pieces of software running, keeping track of what memory is available, and allocating free memory to programmes as needed. The kernel manages all hardware devices and acts as a go-between for hardware devices and running applications.

Shell (What is shell in UNIX)

A shell is a computer programme interface (generally, a command-line interface) that allows users to interact with the operating system using alphanumeric instructions. A shell accepts human-readable commands and utilities, which the kernel processes to perform various tasks.

Programs and Utilities

This part is responsible for taking user instructions in the form of commands. There are a number of commands available in UNIX which you can use to carry out all kinds of tasks.

Files and Directories

This is the location where you can store your data. The files are grouped into directories. The UNIX file system follows hierarchical architecture. 

What is the difference between Unix and Linux?

UNIX is a family of multiuser and multitasking operating systems that first appeared in the early 1970s. It is the foundation block for operating systems and kernels such as Mac and Linux. Below are some of the key differences between Linux and UNIX.

  • Unix is an operating system that is complete and has a kernel as a part of it, whereas Linux is only a kernel.
  • Linux is widely used by developers for almost all purposes, including learning, servers, research and development, while UNIX is used mainly for mainframes.
  • Original UNIX, on the other hand, is not free or open-source.
  • Linux is used on a wide range of computer hardware, including mobile phones, tablet computers, routers, washing machines, mainframes and supercomputers, whereas UNIX is used mainly on internet servers.
  • The Linux kernel is initially created by Linus Torvalds, whereas UNIX is primarily developed by AT&T as well as many other commercial vendors and non-profit organizations.
  • Examples of Linux-based operating systems include Ubuntu, RHEL, Debian, Android, and Kali Linux. UNIX examples include OS X, Solaris, and others.

Examples of using UNIX commands

The UNIX Operating System interacts with the users mainly in the form of commands and shells. Let's look at some of the tasks we can do using the Command Line Interface.


This UNIX command is a very helpful utility as this will allow us to replace the actual command text with another word of our choice. This helps shorten lengthy commands.

$ alias CD="cd Downloads"


This command waits for a process to complete and then returns its exit status. This requires the PID of the process in the input. Below is the syntax for using the wait command.

$ wait [PID]


This command lists all the jobs running in the Operating System. A job is a process that was created from the user instruction. Below is the syntax for this command.

$ jobs [options]


This is abbreviated for "environment." env is a command that is used to print or display environment variables. Below is the syntax for this command.

$ env

Features of UNIX


The Operating system has been written in a high-level language, making it easier to migrate, understand its source code and configure it. On a new machine, the code can be changed and compiled. Users can then select from a wide variety of hardware vendors without being tied to a specific vendor.


Unix is a powerful multitasking operating system, which means that while an active task is running, a background process can also be running. Unix efficiently handles these active and background threads and manages system resources in a fair-share manner.

Operation with Multiple Users

UNIX is a multiuser system that can support a large number of users at the same time. The system enables the sharing of processing power and other resources while ensuring proper privacy and security.

The UNIX shell

The shell is a simple user interface in UNIX that has the ability to provide the services that the user desires. It shields the user from having to be aware of the intricate hardware details.


Namespaces isolate a process's hardware resources by providing it with a separate room where it can access these resources without being interrupted by others. This is advantageous in containerized projects.


A number of Operating Systems are based on UNIX, including Solaris, Darwin, IBM AIX, FreeBSD, NetBSD, etc.

Advantages of UNIX

  • Multiple users can work on the same machine without interfering with each other's resources.
  • Many operating systems are based on UNIX, which helps users choose from multiple options.
  • Multitasking support for managing multiple processes simultaneously.

Disadvantages of UNIX

  • Not suitable for novices as many tasks are carried out using a command line.
  • It is not installed by default in most machines.
  • Not suitable for high graphics and AAA title games


In this article, we discussed what is UNIX Operating System, one of the oldest software still used. We saw how we could interact with the Kernel in UNIX, discussed its features, advantages, and disadvantages, and went through the examples of interacting with UNIX.

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