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Difference Between Linux and UNIX

by NI XCRA F T on FEBRUARY 23, 2006 · 2 5 1 CO MM E NTS · last updated at J UL Y 9 , 2 0 1 0


hat is the difference between Linux and UNIX

operating systems?

UNIX is copyrighted name only big companies are allowed to use the UNIX copyright and name, so IBM AIX and Sun

Solaris and HP-UX all are UNIX operating systems. The Open

Group holds the UNIX trademark in trust for the industry, and manages the UNIX trademark licensing program.

Most UNIX systems are commercial in nature.

Linux is a UNIX Clone

But if you consider Portable Operating System Interface

(POSIX) standards then Linux can be considered as UNIX. To quote from Official Linux kernel README file:

Linux is a Unix clone written from scratch by Linus Torvalds with assistance from a loosely-knit team of hackers across the Net. It aims towards POSIX compliance.


However, "Open Group" do not approve of the construction "Unix-like", and consider it misuse of their UNIX trademark.

Linux Is Just a Kernel

Linux is just a kernel. All Linux distributions includes GUI system + GNU utilities (such as cp, mv, ls,date, bash etc) + installation & management tools + GNU c/c++ Compilers + Editors (vi) + and various applications (such as OpenOffice, Firefox). However, most UNIX operating systems are

considered as a complete operating system as everything come from a single source or vendor.

As I said earlier Linux is just a kernel and Linux distribution makes it complete usable operating systems by adding various applications. Most UNIX operating systems comes with A-Z programs such as editor, compilers etc. For example HP-UX or Solaris comes with A-Z programs.

License and cost

Linux is Free (as in beer [freedom]). You can download it from the Internet or redistribute it under GNU licenses. You will see the best community support for Linux. Most UNIX like

operating systems are not free (but this is changing fast, for example OpenSolaris UNIX). However, some Linux

distributions such as Redhat / Novell provides additional Linux support, consultancy, bug fixing, and training for additional fees.


Linux is considered as most user friendly UNIX like operating systems. It makes it easy to install sound card, flash players, and other desktop goodies. However, Apple OS X is most popular UNIX operating system for desktop usage.

Security Firewall Software

Linux comes with open source netfilter/iptables based firewall tool to protect your server and desktop from the crackers and hackers. UNIX operating systems comes with its own firewall product (for example Solaris UNIX comes with ipfilter based firewall) or you need to purchase a 3rd party software such as Checkpoint UNIX firewall.

Backup and Recovery Software

UNIX and Linux comes with different set of tools for backing up data to tape and other backup media. However, both of them share some common tools such as tar, dump/restore, and cpio etc.

File Systems

 Linux by default supports and use ext3 or ext4 file systems.

 UNIX comes with various file systems such as jfs, gpfs

(AIX), jfs, gpfs (HP-UX), jfs, gpfs (Solaris).

System Administration Tools

1. UNIX comes with its own tools such as SAM on HP-UX. 2. Suse Linux comes with Yast

3. Redhat Linux comes with its own gui tools called redhat-config-*.


However, editing text config file and typing commands are most popular options for sys admin work under UNIX and Linux.

System Startup Scripts

Almost every version of UNIX and Linux comes with system initialization script but they are located in different directories: 1. HP-UX - /sbin/init.d

2. AIX - /etc/rc.d/init.d 3. Linux - /etc/init.d

End User Perspective

The differences are not that big for the average end user. They will use the same shell (e.g. bash or ksh) and other development tools such as Perl or Eclipse development tool.

System Administrator Perspective

Again, the differences are not that big for the system

administrator. However, you may notice various differences while performing the following operations:

1. Software installation procedure 2. Hardware device names

3. Various admin commands or utilities 4. Software RAID devices and mirroring 5. Logical volume management

6. Package management 7. Patch management


UNIX Operating System Names

A few popular names: 1. HP-UX

2. IBM AIX 3. Sun Solairs 4. Mac OS X 5. IRIX

Linux Distribution (Operating System) Names

A few popular names:

1. Redhat Enterprise Linux 2. Fedora Linux

3. Debian Linux

4. Suse Enterprise Linux 5. Ubuntu Linux

Common Things Between Linux & UNIX

Both share many common applications such as: 1. GUI, file, and windows managers (KDE, Gnome) 2. Shells (ksh, csh, bash)

3. Various office applications such as OpenOffice.org 4. Development tools (perl, php, python, GNU c/c++

compilers) 5. Posix interface


Fig.01: UNIX Desktop - IRIX 6.5 Desktop


Fig.02: Linux KDE desktop environment

UNIX and Linux Hardware

Commercial UNIX hardware has more advanced initial boot options such as:

 Decide how to boot

 Check system health

 Set hardware parameters etc

The BIOS that is standard in PCs which is used by Linux has few, of these features. UNIX hardware or servers are pretty expensive as compare to Linux server systems.

Further readings:

Following documents or URL should help anyone to get more idea:


 UNIX System Management and Security: Differences

between Linux, Solaris, AIX and HP-UX

 40 years of Unix

(Image credit IRIX and KDE wikipedia articles)




Linux vs Unix

Diffen › Technology › Computers › Software › Operating Systems

Linux is an open source, free to use operating system widely used for computer hardware and software, game

development, tablet PCS, mainframes etc. Unix is an operating system commonly used in internetservers, workstations and PCs by Solaris, Intel, HP etc.

Comparison chart

Improve this chart Linux

 Currently 3.96/5  1  2  3  4  5 Rating: 4.0/5 (671 votes) Unix  Currently 3.87/5  1  2  3  4  5 Rating: 3.9/5 (383 votes)

What is it?: Linux is an example of Open Source software development andFree Operating System (OS).

Unix is an operating system that is very popular in universities, companies, big enterprises etc.


Improve this chart Linux  Currently 3.96/5  1  2  3  4  5 Rating: 4.0/5 (671 votes) Unix  Currently 3.87/5  1  2  3  4  5 Rating: 3.9/5 (383 votes)

downloaded freely, distributed through magazines, Books etc. There are priced versions for Linux also, but they are normally cheaper than Windows.

different cost structures

Price: Free but support is available for a price.

Some free for development use (Solaris) but support is available for a price.

User: Everyone. From home users to developers and computer enthusiasts alike.

Unix operating systems were developed mainly for mainframes, servers and workstations. The Unix environment and the client-server program model were essential elements in the development of the Internet

Manufacturer: Linux kernel is developed by the community. Linus Torvalds oversees things.

Three bigest distributions are Solaris (Oracle), AIX (IBM) & HP-UX Hewlett Packard.

Usage: Linux can be installed on a wide variety of computer hardware, ranging from mobile phones, tablet computers and video game consoles, to mainframes and supercomputers.

The UNIX operating system is used in internet servers, workstations & PCs. Backbone of the majority of finance infastructure and many 24x365 high availability solutions.


PA-Improve this chart Linux  Currently 3.96/5  1  2  3  4  5 Rating: 4.0/5 (671 votes) Unix  Currently 3.87/5  1  2  3  4  5 Rating: 3.9/5 (383 votes)

RISC and many others.

Architectures: Originally developed for Intel's x86 hardware, ports available for over two dozen CPU types including ARM

is available on PA-RISC and Itanium machines. Solaris also available for x86/x64 based systems.

Killer features: Ksplice - kernel update without reboot

ZFS - Next generation filesystem Dtrace - dynamic kernel tracing

GUI: Linux typically provides two GUIs, KDE and Gnome. But Linux GUI is optional.

Initially Unix was a command based OS, but later a GUI was created called Common Desktop

Environment. Most distributions now ship with Gnome.

File system support:

Ext2, Ext3, Ext4, Jfs, ReiserFS, Xfs, Btrfs, FAT, FAT32, NTFS

jfs,gpfs,hfs,ufs,xfs,zfs format

Text mode interface:

BASH (Bourne Again SHell) is the Linux default shell. It can support multiple command interpreters.

Originally the Bourne Shell. Now it's compatible with many others including BASH, Korn & C.

Security: Linux has had about 60-100 viruses listed till date. None of them actively spreading nowadays.

A rough estimate of UNIX viruses is between 85 -120 viruses reported till date.

Development and Distribution:

Linux is developed by Open Source development i.e. through sharing and collaboration of code and features

Unix systems are divided into various other flavors, mostly developed by AT&T as well as various commercial


Improve this chart Linux  Currently 3.96/5  1  2  3  4  5 Rating: 4.0/5 (671 votes) Unix  Currently 3.87/5  1  2  3  4  5 Rating: 3.9/5 (383 votes)

through forums etc and it is distributed by various vendors such as Debian, Red Hat, SUSE, Ubuntu, GentuX etc.

vendors and non-profit organizations.

Threat detection and solution:

In case of Linux, threat detection and solution is very fast, as Linux is mainly community driven and whenever any Linux user posts any kind of threat, several developers start working on it from different parts of the world

Because of the proprietary nature of the original Unix, users has to wait for a while, to get the proper bug fixing patch. But these are not as common.

Inception: Inspired by MINIX (a Unix-like system) and eventually after adding many features of GUI, Drivers etc, Linus Torvalds developed the framework of the OS that became LINUX in 1992. The LINUX kernel was released on 17th September, 1991

In 1969, it was developed by a group of AT&T employees at Bell Labs and Dennis Ritchie. It was written in “C” language and was designed to be a portable, tasking and multi-user system in a time-sharing configuration.





Command-line-wise, almost none, although this has been changing (for better or worse). Linux has a much larger market appeal and following than any commercial UNIX. GUI-wise there are also no major differences--Linux, as most other UNIXes, uses an X-Windowing system.

The major differences:

 Linux is free, while many UNICES (this is supposed to be the plural of UNIX), are very expensive. The same for applications--many good applications are available on Linux free. Even the same commercial application (if you wanted to buy one) typically costs much more for a commercial UNIX than for Linux.

 Linux runs on many hardware platforms, the commodity Intel-x86/IBM-spec personal computers being the most prominent. In contrast, a typical UNIX is proprietary-hardware-bonded (and this hardware tends to be much more expensive than a typical PC clone).

 With Linux, you are in charge of your computer, whereas on most UNICES you are typically confined to be an "l-user" (some administrators pronounce it "loser").

 Linux feels very much like DOS/Win in the late 80s/90s, but is much sturdier and richer, while a typical UNIX account feels like a mainframe from the 60s/70s.

 Some UNICES may be more mature in certain areas (for example, security, some engineering applications, better support of cutting-edge hardware). Linux is more for the average Joe who wants to run his own server or engineering workstation.




Hello Friend,

Unix and Linux are different operating systems. The main difference is between their interface type or method. Unix is a CUI operating system i.e. It is a character user interface operating system while Linux is a GUI operating system. GUI means graphical user interface. Character user interface is that system in which a human can interface with the system via characters only. You can use your keyboard to give inputs to your unix operating system while in Graphic user interface you can use both images and characters to give inputs to your system. Mouse can only be used in graphic user interface, while keyboard in both character user interface as well as in graphic user interface.

If you are familiar with windows operating system then you can consider Unix as MS-Dos and Linux as MS - Windows.

I think now the difference is clear to you. With best regards,

Sunil Saharan




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