Linux AdministrationUnit 1Introduction to LinuxCompiled by Bhavesh Shah

Compiled by Bhavesh Shah*

OverviewIntroduction to UnixIntroduction to GNUIntroduction to LinuxLinux DistributionsLinux Pros & ConsCompiled by Bhavesh Shah

Compiled by Bhavesh Shah*

Introduction to UnixPrior to 70'sEvery computer had different operating systemSoftware customized for specific purposeSoftware made for one computer didn't run on another system

In 1969, team of developers at AT&T Bell Labs started working on a solution to address these compatibility issuesA new operating system named UNIX was developed with featuresSimple & elegantWritten in C programming & not assembly codeAble to recycle code

Compiled by Bhavesh Shah

Compiled by Bhavesh Shah*

Unix PhilosophySimplicity Unix utilities are simple, small & easy to understandFocus Unix focuses on single programs as they are easier to improveReusable Components applications in Unix are available as libraries. This makes interfaces easily programmable & flexibleFilters Many Unix applications can be used as filtersOpen File Formats It enables users to use standard tools to change & search for configuration items & to develop new tools for performing new functionsFlexibility can't anticipate how users will use your programCompiled by Bhavesh Shah

Compiled by Bhavesh Shah*

Introduction to GNUSource code of Unix operating system was shared with rest of world at no costBy 1975, AT&T started selling Unix commercially (about half source code was written by others)This led to legal battle which resulted in 2 versions of Unix official AT&T Unix & free BSD Unix

The 80's saw many companies emerging with their own version of UnixIBM created AIX, Sun created SunOS, HP created HP-UX and many othersThis resulted in mess of Unix dialects & many different ways to do the same things

Compiled by Bhavesh Shah

Compiled by Bhavesh Shah*

GNU & Free Software FoundationRichard Stallman aimed at ending this era of Unix separation by starting the GNU projectHis goal was to make an operating system that was freely available to everyone & where everyone could work together

The Free Software Foundation set up by Richard Stallman, a pioneer of the free software concept, started the GNU Project, an attempt to create an operating system & development environment that would be compatible with UNIX, but not suffer the restrictions of the proprietary UNIX name & source codeGNU project provides many software applications under the GNU General Public License (GPL) which are close to those found on Unix systemsCompiled by Bhavesh Shah

Compiled by Bhavesh Shah*

GNU toolsA few major examples of software from the GNU Project distributed under the GPL follow:GCC: The GNU Compiler Collection, containing the GNU C compilerG++: A C++ compiler, included as part of GCCGDB: A source codelevel debuggerGNU make: A version of UNIX makeBison: A parser generator compatible with UNIX yaccbash: A command shellGNU Emacs: A text editor and environment

Many other packages have been developed & released using free software principles & the GPL includingspreadsheets, source code control tools, compilers & interpreters, Internet tools, graphical image manipulation tools such as the Gimp, and two complete object-based environments: GNOME & KDE

There is now so much free software available that with the addition of the Linux kernel it could be said that the goal of a creating GNU, a free UNIX-like system, has been achieved with LinuxTo recognize the contribution made by GNU software, many people now refer to Linux systems in general as GNU/LinuxCompiled by Bhavesh Shah

Compiled by Bhavesh Shah*

Introduction to LinuxLinux was developed by Linus Torvalds at the University of Helsinki in the 90'sLinus wrote a new POSIX compliant kernel, POSIX is still the standard for UNIXMany people embraced this kernel with the GNU toolsToday more than 90 percent of supercomputers (including the complete top 10), more than half of all smart phones, many millions of desktop computers, around 70 percent of all web servers, a large chunk of tablet computers, and several appliances (DVD-players, washing machines, DSL modems, routers, ...) run LinuxIt is by far the most commonly used operating system in the worldCompiled by Bhavesh Shah

Compiled by Bhavesh Shah*

Linux DistributionsLinux is actually just a kernel, which can be obtained, compiled and installed on a machine and then many other freely distributed software programs can be obtained and installed to make a complete Linux installationMany people have put together ready-to-install distributions (often called flavours), usually downloadable or on CD-ROMs or DVDs, that contain not just the kernel but also many other programming tools and utilitiesSome well-known distributions are Red Hat Enterprise Linux and its community-developed cousin Fedora, Novell SUSE Linux and the free openSUSE variant, Ubuntu Linux, Slackware, Gentoo, and Debian GNU/LinuxThe distributions usually come with a setup program and additional documentation to help you install your own Linux systemCompiled by Bhavesh Shah

Compiled by Bhavesh Shah*

Linux ProsLinux is freeLinux is portable to any hardware platformLinux was made to keep on runningLinux is secure and versatileLinux is scalableThe Linux OS and most Linux applications have very short debug-timesCompiled by Bhavesh Shah

Compiled by Bhavesh Shah*

Linux ConsThere are far too many different distributionsLinux is not very user friendly and confusing for beginnersIs an Open Source product trustworthy?Compiled by Bhavesh Shah

Compiled by Bhavesh Shah*

Questions?Please don't keep it to yourself ?Compiled by Bhavesh Shah

Compiled by Bhavesh Shah**

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