Linux Intro

Compiler: A compiler is a special program that processes statements written in a particular programming language and turns them into machine language or "code" that a computer's processor uses. Assembler: Software that translates assembly language into machine language. Contrast with compiler, which is used to translate a high-level language, such as COBOL or C, into assembly language first and then into machine language. Interpeter A high-level programming language translator that translates and runs the program at the same time. It translates one program statement into machine language, executes it, and then proceeds to the next statement. Linker: A program that combines one or more files containing {object code} from separately compiled program {modules} into a single file containing loadable or executable code Loader A loader is a component that locates a given program (which can be an application or, in some cases, part of the operating system itself) in offline storage (such as a hard disk), loads it into main storage (in a personal computer, it's called random access memory), and gives that program control of the computer Operating System An operating system (sometimes abbreviated as "OS") is the program that, after being initially loaded into the computer by a boot program, manages all the other programs in a computer.

Features of Linux: Multiprocessing: Multiprocessing is the use of two or more central processing units (CPUs) within a single computer system. The term also refers to the ability of a system to support more than one processor and/or the ability to allocate tasks between them Multiprocessing sometimes refers to the execution of multiple concurrent software processes in a system as opposed to a single process at any one instant. Multi Tasking: Multitasking, in an operating system, is allowing a user to perform more than one computer task (such as the operation of an application program) at a time.

Shell Programming Bourne shell (sh) This is the original Unix shell written by Steve Bourne of Bell Labs. It is available on all UNIX systems. This shell does not have the interactive facilites provided by modern shells such as the C shell and Korn shell. You are advised to to use another shell which has these features. The Bourne shell does provide an easy to use language with which you can write shell scripts. . C shell (csh) This shell was written at the University of California, Berkeley. It provides a C-like language with which to write shell scripts - hence its name. TC shell (tcsh)

This shell is available in the public domain. It provides all the features of the C shell together with emacs style editing of the command line. Korn shell (ksh) This shell was written by David Korn of Bell labs. It is now provided as the standard shell on Unix systems. It provides all the features of the C and TC shells together with a shell programming language similar to that of the original Bourne shell. It is the most efficient shell. Consider using this as your standard interactive shell. Bourne Again SHell (bash) This is a public domain shell written by the Free Software Foundation under their GNU initiative. Ultimately it is intended to be a full implementation of the IEEE Posix Shell and Tools specification. This shell is widely used within the academic commnity. bash provides all the interactive features of the C shell (csh) and the Korn shell (ksh). Its programming language is compatible with the Bourne shell (sh).