Contents.. What is UNIX History of UNIX Why use UNIX UNIX Structure Commands File Structure Applications of UNIX Advantages and Disadvantages of UNIX
What is UNIX:- UNIX once referred to a specific operating system. It is available in variety of “flavors” like as BSD, sunOS, Solaris, etc. UNIX operating system is a large program(mostlycoded in C) that turns the computer into a usablemachine. It provides a number of facilities: Management of hardware resources Directory and file system Loading/ execution/ suspention of programs
Cont… UNIX is not a single operating system. It is a family ofoperating system. It is a multitasking, multi-user computer operatingsystem.
History of Unix:- UNIX was first developed in 1969 by a group of AT&TBell labs, including Ken thompson, Dennis Ritchie. It was first developed in assembly language, and in1973 it was recoded in C. In 1990 LINUX was developed which is a flavor ofUNIX. Now UNIX is wide spread and available from manysources.
Why use UNIX:- Multi-user operating system Multitasking operating system Time sharing operating system Portability Network capability Easy to program I/O independence Communicating among users
User programs:-The UNIX System contains several hundred utilities or userprograms. Commands are also known as tools, because theycan be used separately or put together in various ways to carryout useful tasks.Kernel:-The kernel is the part of the operating system thatinteracts directly with the hardware of a computer, throughdevice drivers that are built into the kernel. It provides sets ofservices that can be used by programs
Cont..Shell:-The shell reads your commands and interprets them asrequests to execute a program , which it then arranges to havecarried out. Because the shell plays this role, it is called acommand interpreter.
Command Usepasswd Change your passworddate Get the current date and timecal Display a calendarwho List all users who are currently logged infinger username Get information about usernamewrite username Send a chat message to usernametalk username Open a chat session with usernamemesg ymesg nAccept or block incoming messagesman command Get information about commandmailxmailx addressRead e-mail messages, or send an e-mail to addressexit Log out of the systemshutdown poweroff Turn off the machineCOMMANDS:-
File structure:-the UNIX file system is called a hierarchical file system. Withinthe UNIX System, there is no limit to the number of files anddirectories you can create in a directory that you own. Filesystems of this type are often called tree-structured filesystems,
Extension File Type Extension File Type.au Audio .mpg, .mpeg MPEG video.c C language source code .o Object file (compiled andassembled code).cc C++ source code .pl Perl script.class Compiled Java file .ps PostScript file.conf Configuration file .py Python script.d Directory .sh Bourne shell script.gif GIF image .tar tar archive.gz Compressed with gzip .tar.Z, .tar.gz Files that have been archivedwith tar and then compressed.h Header file for a C program .tex Text formatted with Tex/LaTeX.html Webpage .txt ASCII text.jar Java archive .uu, .uue Uuencoded file.java Java source code .wav Wave audio.jpg, .jpeg JPEG image .z Compressed with pack.log Log file .Z Compressed with compress
Application Of Unix:- Applications built using UNIX commands, tools, and programs horizontal applications like as government, industry, andeducation Others are industry-specific and are known as verticalapplications web browsers and web server application Another important class of applications deals with multimedia.Such applications let users create and view multimedia files,including audio, images, and video.
Advantages of UNIX:- Unix is multitasking and multi-user operating system. Access control and security. A powerfully unified file system. Optimized for program development. Available on wide variety of machines.
Disadvantages:- Software incompatibility incompatible disk formats.