What are they?
Where did they originate?
Scripting languages have been around since the 1960s. IBM's JCL, Rexx and Unix shells are used to write shell scripts and macros and automate tasks. Perl and TCL appeared in the late 1980s, and Python in the 1990s.
What are they for?
John Ousterhout, creator of TCL, said, "System programming languages were designed for building data structures and algorithms from scratch, starting from the most primitive computer elements. In contrast, scripting languages are designed for gluing: they assume the existence of a set of powerful components and are intended primarily for connecting components together.
"System programming languages are strongly typed to help to manage complexity, while scripting languages are typeless to simplify connections between components and provide rapid application development."
What makes them special?
They are high-level languages designed to make fewer demands on the programmer and the CPU. "Getting the job done fast is typically prioritised above getting the job done so it runs faster," said a white paper by scripting tools specialist Active State. "This approach makes sense when one considers that many programs are run only periodically, and take effectively no time to execute, but can take months to write."
Some claim that development times can be slashed when scripting languages replace C++ or Java. Traditionalists may condemn them as not suitable for serious coding, but scripting champions point out that less time coding means more time on testing and integration.
How difficult are they?
Because they are English-like, and users do not need to grapple with concepts such as types and classes, they can be learned and used quickly. TCL is described as having "an almost zero learning curve".
Where are they used?
Being dynamically typed means scripting languages are able to handle known and unpredictable objects. This is important in web applications, which need to interact with unknown third-party applications.
"The explosion of database-backed websites developed and maintained by non-engineers led to the sustained explosion of PHP use worldwide," said Active State's white paper.
What systems do they run on?
The main scripting languages are available, or are in the process of being made available, for most platforms, although dependence on volunteer enthusiasts means they are sometimes available for obscure machines before mainstream platforms.
Not many people know that
Scripting languages are part of what has been called the Lamp - Linux, Apache, MySQL, Perl/PHP/Python - platform.
What is coming up?
As application requirements become more dynamically changeable, scripting languages could take over from traditional programming languages.
There are plenty of free tutorials for scripting languages on the web.
For tcl, click here >>
Rates of pay
PHP and Perl developers can look for £24,000 to £35,000, either with other Lamp skills or with traditional languages such as C++. Jobs requiring TCL tend to be more technical, are often associated with Unix, and often pay more.
This was first published in October 2004