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linux and shell programming for information.pptx
- 1. Linux and ShellProgramming II-B.Sc INFORMATION TECHNOLOGY
- 2. Unit:I Introduction to LINUXOperating System Introduction The LINUX Operating System
- 3. Operating System Anoperating system is an interface between a user and a computer. manages system resources and computer hardware manages interactions between user and system by accepting input from user, interpreting the input and generating the output OS forms the base on which any application software can be developed
- 4. Some popularoperating systems are Linux Unix Microsoft DOS. Microsoft Windows 95/98. Microsoft windows NT Server 4.0. Apple MAC.
- 5. Functions Of OperatingSystem Command Interpretation Process Management Memory Management Input/Output operations and Peripheral Management File Management
- 6. Command Interpretation A commandinterpreter is a system software that understands and executes commands that are entered interactively by a human or from an another program. CPU can interpret only binary codes OS translates the command to binary codes It provides an interface between the user and the computer.
- 7. Process Management Processis defined as program in execution To run, pgm need to be in main memory(RAM) OS loads program from memory and executes one at a time In multiprogramming, many programs run at a time refers to the activities involved in managing the execution of multiple processes in an operating system. It includes creating, scheduling, and terminating processes, as well as allocating system resources such as CPU time, memory, and I/O devices.
- 8. Memory Management OSallocates memory to processes Main memory stores the process that are currently running Hard disks stores the processes that are not being executed hard disks temporary storage device Processes can be executed only they are in the main memory The task of subdividing the memory among different processes is called Memory Management.
- 9. Input/Output operations andPeripheral Management OS enables I/O devices to perform I/O operations In I/O input, data flows from the device to a computer. I/O output operations refer to data signals sent by the output device in response to the data input. OS maintains communication between devices and CPU Peripheral -a device connected to a computer to provide communication (such as input and output) or auxiliary functions (such as additional storage)
- 10. File management Filemanagement in an operating system refers to the set of processes and techniques involved in creating, organizing, accessing, manipulating, and controlling files stored on storage devices such as hard drives, solid-state drives, or network storage.
- 11. Types of Systems Singleuser systems Multi User Systems
- 12. Single user systems In a single user system, only one user can access the computer system at a time. commonly found in home computers. Example: personal computer small and can run programs that perform variety of tasks Low cost and wide range of software availability, pc became popular There are two types of single user operating systems called single user, single task operating system and single user, multi-task operating system.
- 13. Single-user OS MS-DoS isa Single user OS It contains Command Line Interface<CLI>
- 14. Multi User Systems More than one user can work simultaneously Can run multiple process concurrently and share hardware resources allows multiple users to access the computer at the same time. The operating system manages the memory and resources among the various users according to the requirements. The task of one user will not affect the tasks of the other users.
- 15. Unix andLinux are two examples of multi user operating systems Users can either use the system console or terminals to connect to the multiuser systems Remote users can use communication lines
- 16. Basic Conceptsof Multiuser systems CPU is more powerful than single user system supports multiprogramming and multitasking performs more than one task simultaneously consists of computer with several terminals attached 2 types of terminals Dump consists of keyboard and monitor no hard disk or CPU acts as an interface between user and multiuser system
- 17. Smart Hasits own CPU and pheripherals and can work independent of multiuser systems can work on any OS that is loaded on to its hard disk It can also be connected to central unit Multi user OS Linux, Unix and Windows NT multi user OS more than one user can connect to the system and work at a time
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- 19. History of LINUX 1969-Ken Thompson and Dennis Ritchie general purpose osUNIX all oswritten in assembly language 1973 Ken and Dennis rewrote the unix os in C 1974 UNIX was licensed to universities for education purpose 1984 Richard Stallman free s/w ffoundation began the project to create the free version of UNIX FSF developed large no of tools
- 20. 1991, LinusTorvalds developed a kernel called Linux 1992,Linux combined with incomplete GNU and form free OS GNU/Linux GNU/Linux is commonly called as Linux OS The name Linux is a combination of his first name, Linus, and Unix, the operating system that inspired his projects
- 21. Linux officialmascot the Linux penguin called Tux Linux free software text editor, browsers and programming tools
- 22. Architecture of Linuxsystem The Linux operating system's architecture mainly contains: The Kernel, Shells, Application programs, Shell utility, Hardware.
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- 24. Kernel Coreof Linux OS Kernelos pgm controls the resources of the computer and allocate them to different users and tasks directly interact with hardware User cant directly interact with kernel The logon process initiates separate and interactive program called shell for each user SHELL Linux has a simple user interface called Shell User can interact with the computer by using Shell It is an interface among the kernel and user Common shells in Linux are tcsh,bash,csh,ksh,sh
- 25. Linux Utilitiesand Application Programs Linux utilities/Commands collection of programs that service processing requirements programs are started by shell Application programs are available from independent software vendors
- 26. Difference between Linuxand Unix
- 27. Linux Operating SystemFeatures Multiprogramming Time sharing Multitasking Virtual Memory Cron Scheduler Webserver Licensing
- 28. Multiprogramming: allowsseveral programs to be executed simultaneously by different users Time Sharing: OS has to manage various programs simultaneously Programs are queued and CPU is shared among programs Each program receives CPU time for a specific period Multitasking: The ability of any OS to handle execution of multiple tasks When the task is waiting for the completion of other task , CPU instead of wasting time, it executes the next task Kernel is responsible for scheduling the task Virtual Memory: Physical memory not sufficient logical portion of hard disk can be utilized as artificial/virtual memory The programs which are not used often are stored in this memory
- 29. SAMBA SERVERMESSAGE BLOCK PROTOCOL (SMB) protocol used by MS OS to share files and printers SAMBA suite of programs that implement SMB protocol in Linux Using SMB, Linux files can be shared with Windows OS and viceversa Cron Scheduler: Linux has a scheduler program called Cron Cron run programs /scripts/commands at scheduled time Licensing Linux is licensed under GNU General Public License Licensing for Red Hat Linuxperson can make any no of copies of s/w and distribute it freely/ fix price for it
- 30. Web Server runs on the OS and enables the users to access resources in the web pages Web server can enable user to access resources on WAN Web server is commonly referred to as computer that delivers web pages
- 31. Shells Available inLINUX The Bourne Shell Executable file name is denoted as sh It was written by Steve Bourne at AT&T Bell Labs. It is the original UNIX shell and is stored in /bin directory It is faster and more preferred. It is default shell for Solaris OS. For the Bourne shell the: Command full-path name is /bin/sh and /sbin/sh, Non-root user default prompt is $, Root user default prompt is #.
- 32. The CShell Executable file name is denoted as csh. Bill Joy created it at the University of California at Berkeley. It incorporated features such as aliases and command history. It includes helpful programming features like built-in arithmetic and C-like expression syntax. In C shell: Command full-path name is /bin/csh Non-root user default prompt is hostname % Root user default prompt is hostname #.
- 33. The KornShell It is denoted as ksh It was written by David Korn at AT&T Bell Labs. It is a superset of the Bourne shell. Combines the features of Bourne and C shell. It includes features like built-in arithmetic and C-like arrays, functions, and string- manipulation facilities. It is faster than C shell. For the Korn shell the: Command full-path name is /bin/ksh Non-root user default prompt is $ Root user default prompt is #.
- 34. Restricted Shell provide limited access on the OS to the user Used for guest users who need limited access and permissions Use restricted shell to restrict the users of the OS to a limited environment
- 35. Bash shellor Bourne-Again Shell Denoted as bash Product of FSF GNU’s project Default shell for most Linux OS It includes features from Korn and Bourne shell. It stores all command used in current session and also in previous session In Red Hat Linux,Sh command is symbolic link to bash For the GNU Bourne-Again shell the: Command full-path name is /bin/bash, Default prompt for a non-root user is bash-g.gg$ (g.ggindicates the shell version number like bash-3.50$), Root user default prompt is bash-g.gg#.
- 36. Tcsh shell Stands for Tom’s C shell Also known as tc shell In linux, csh command is symbolic link to tcsh shell A Shell A shell developed by kenneth Almquist at Berkley University Emulates the Bourne shell suitable for computers with limited memory executable file name for A shell is ash
- 37. Z Shell Denoted by zsh Shell created by Paul Falstad in 1990 Offers the features of tcsh and korn shell Provides utilities and extensive documentation Command full-path name is /bin/zsh, Default prompt for a non-root user is abhishekaslk(user)% Root user default prompt is root@abhishekaslk(user):~#