Script::-
A type of computer code than can be directly executed by a program that understands the language in which the script is written. Scripts do not need to be compiled into object code to be executed.
Scripting Language::-
A high-level programming language that is interpreted by another program at runtime rather than compiled by the computer’s processor as other programming languages (such as C and C++) are. Scripting languages, which can be embedded within HTML, commonly are used to add functionality to a Web page, such as different menu styles or graphic displays or to serve dynamic advertisements. These types of languages are client-side scripting languages, affecting the data that the end user sees in a browser window. Other scripting languages are server-side scripting languages that manipulate the data, usually in a database, on the server.
A scripting language differentiates itself from other typical languages in that they are usually simpler to learn and use as well as not needing to be compiled. The language is interpreted at run-time so you can execuate instructions immediately.
Scripting languages came about largely because of the development of the Internet as a communications tool. JavaScript, ASP, JSP, PHP, Perl, Tcl and Python are examples of scripting languages.
Why Scripting Language??
Scripting languages are often designed for interactive use, having many commands that can execute individually, and often have very high level operations (for example, in the classic UNIX shell (sh), most operations are programs themselves).
Such high level commands simplify the process of writing code. Programming features such as automatic memory management and bounds checking can be taken for granted. In a 'lower level' or non-scripting language, managing memory and variables, and creating data structures tends to consume more programmer effort and lines of code to complete a given task. In some situations, this is well worth it for the resulting fine-grained control. The scripter typically has less flexibility to optimize a program for speed or to conserve memory.
For the reasons noted above, it is usually faster to program in a scripting language, and script files are typically much smaller than, for example,equivalent C program files. The flip side can be a performance penalty: scripting languages, often interpreted, may be significantly slower to execute and might consume more memory when running. In some cases, however, e.g. with small scripts of some tens of lines, the write-time advantage far outweighs the run-time disadvantage. Also, this argument gets stronger with rising programmer salaries and falling hardware costs.
-Scripting languages aren’t intended for writing applications from scratch; they are intended Primarily for plugging together components (which are usually written in systems programming languages).
-Scripting languages are often used to extend the features of components but they are rarely used for complex algorithms and data structures.
-In order to simplify the task of connecting components, scripting languages tend to be typeless.
__________Types of scripting languages_____________
1 Job control languages and shells::
A major class of scripting languages has grown out of the automation of job control, which relates to starting and controlling the behavior of system programs. Many of these languages' interpreters double as command line interfaces such as the Unix shell or the MS-DOS COMMAND.COM.
2 GUI Scripting::
With the advent of Graphical user interfaces came a specialized kind of scripting language for controlling a computer. These languages interact with the same graphic windows, menus, buttons, and so on that a system generates. These languages are typically used to automate
repetitive actions or configure a standard state. In principle, they could be used to control any application running on a GUI-based computer; but, in practice, the support for such languages depend on the application and operating system. Such languages are also called "macro languages" when control is through keyboard interaction.
3 Application-specific languages::
Many large application programs include an idiomatic scripting language tailored to the needs of the application user. Likewise, many computer game systems use a custom scripting language to express the programmed actions of non-player characters and the game environment.
Languages of this sort are designed for a single application; and, while they may superficially resemble a specific general-purpose language (e.g. QuakeC, modeled after C), they have custom features that distinguish them.
4 Web programming languages
An important type of application-specific scripting language is one used to provide custom functionality to dynamic web pages. Such
languages are specialized for web applications and other Internet uses.
4.1 Server-side
4.2 Client-side
5 Text processing languages::
The processing of text-based records is one of the oldest uses of scripting languages. Many, such as Unix's awk and, later, Perl, were originally designed to aid system administrators in automating tasks that involved Unix text-based configuration and log files. Perl is a special case originally intended as a report-generation language, it has grown into a full-fledged applications language in its own right.
6 General-purpose dynamic languages::
Some languages, such as Perl, began as scripting languages but were developed into programming languages suitable for broader purposes.Other similar languages -- frequently interpreted, memory-managed, or dynamic -- have been described as "scripting languages" for these similarities,even if they are more commonly used for applications programming.
7 Extension/embeddable languages::
A number of languages have been designed for the purpose of replacing application-specific scripting languages by being embeddable in application programs. The application programmer (working in C or another systems language) includes "hooks" where the scripting language can
control the application. These languages serve the same purpose as application-specific extension languages but with the advantage of allowing some transfer of skills from application to application.
Advantages::
-Scripting languages are a blend of those features that make a programmer productive
and attempt to leave out everything else;
-In particular, they tend to have automatic memory management and powerful operations
tightly built in (rather than relying on libraries).
-They tend not to have strong typing rules and access rules that restrict the programmer
from doing certain things.
Thanks to wiki &all the sites i forgot to mention!!!!
The Simpsons' transition to the big screen has proved a success, with their first movie topping the North American box office in its opening weekend.The film, which sees the animated family chased out of Springfield for causing an environmental disaster, took $72m (£36m) between Friday and Sunday.