Why All These Scripting Languages

Over the last fifteen years, there has been a fundamental change in the way people write computer programs. The transition from system programming languages like C or C++ to scripting languages like Perl or PHP has risen up because of the use of the internet as a communication tool.

The main characteristics of a scripting language is its ease of usage and they are usually interpreted from source code unlike system programming languages.
Scripting programming languages such as Python, Rexx, Unix shells, Perl and Tcl represent a very unique style of programming than system programming languages. These languages are intended for writing programs from scratch and fixing components together.

There are a lot of scripting languages in the system and here are some of the popular ones;

Perl (Practical Extraction and Report Language). This is a popular string processing language for writing small scripts for system administrators and web site maintainers. Much web development is now done using Perl.
JavaScript, perhaps the most publicised and well-known scripting language was initially developed by Netscape as LiveScript to allow more functionality and enhancement to web page authoring that raw HTML could not accommodate.
VBScript, a cut-down version of Visual Basic, used to enhance the features of web pages in Internet Explorer.
Python is a widely used general purpose, high-level programming language. Its design philosophy emphasizes code readability, and its syntax allows programmers to express concepts in fewer lines of code than would be possible in languages such as C. The language provides constructs intended to enable clear programs on both a small and large scale.
PHP is a server-side scripting language designed for web development but also used as a general purpose programming language. PHP code is interpreted by a web server with a PHP processor module which generates the resulting web page: PHP commands can be embedded directly into an HTML source document rather than calling an external file to process data. It has also evolved to include a command line interface capability and can be used in standalone graphical application.

New languages often learn from existing languages and add, remove and combine features in a new way. There is a few different paradigms like object oriented and functional and many modern languages try to mix features from them both.

For the same reason there are hammers, screwdrivers, handsaws, bandsaws, jackhammers, crowbars, and a host of other tools: not every language is perfect for every task. Some languages are targeted at specific problem domains

Also, for the same reason that shirts come in different colors: some people just like the "style" of one language over another.

And, of course, a lot of programmers find it fun to invent a new language, just to see what happens, or perhaps because they have some knowledge about languages and want to scratch an itch, or try out some ideas.