A scripting language or script language is a programming
language that supports the writing of scripts, programs written for a software
environment that automate the execution of tasks which could alternatively be
executed one-by-one by a human operator. Environments that can be automated
through scripting include software applications, web pages within a web
browser, the shells of operating systems, and several general purpose and
domain-specific languages such as those for embedded systems. Scripting is
usually a property of the primary implementations of a language, although many
languages are not very suited to this kind of implementation.
Typically, a scripting language is characterized by the
following properties: Ease of use. Scripting languages are intended to be very
fast to pick up and author programs in. This generally implies relatively
simple syntax and semantics. OS facilities - especially file system and
related, built in with easy interfaces. Scripting is usually aimed at desktops,
limiting the portability needs of the pre-built libraries. Interpreted from
source code - to give the fastest turnaround from script to execution. On a
desktop, the performance of even a slow interpreter is often non-problematic.
In comparison, non-scripting languages intended for large programs are often
precompiled in at least some sense for superior performance.
Relatively loose structure. It would be difficult to use Java
as a scripting language due to the rules about which classes exist in which
files - contrast to Python, where it's possible to simply define some functions
in a file. Scripts can be written and executed "on-the-fly", without
explicit compile and link steps; they are typically created or modified by the
person executing them. A scripting language is usually interpreted from source
code or bytecode. By contrast, the software environment the scripts are written
for is typically written in a compiled language and distributed in machine code
form; the user may not have access to its source code, let alone be able to
modify it.
The spectrum of scripting languages ranges from very small
and highly domain-specific languages to general-purpose programming languages.
The term script is typically reserved for small programs.
