Scripting languages come under the domain of programming languages. Scripting languages are such languages where instructions are written for a runtime environment. The scripts written do not need compilation and are only interpreted. Scripting languages can basically be said as programming languages designed to integrate and communicate with other programming languages. Scripting languages are mostly used for automating the executing of some tasks.
Programming languages are formal languages comprising a set of instructions that produce various kinds of output. Programming languages are used in computers to execute instructions and give results depending on them. The history of programming languages goes back to as old as the 1800s. The programming languages were not typed on the computer as we see now, because the computer then was not like today. There were no screens, CPU, keyboard, mouse, etc. Different unique machines have different mechanisms to take commands as input and process them to give the output. Input/output in those computers or machines was also very different. Some used punched cards; some used music boxes, pianos, etc. Since then, programming languages have evolved greatly.
Programming languages have a syntax or rules according to which any statement of a particular language is written. There is a compiler, a software that scans the program to check for the grammar (syntax check), semantics (the statements are meaningful and can be executed). The compiler is also tasked with creating the executable file of the source code, which is run/executed in reality to produce the output.
Now there are some programming languages, which are compiled, and there are also some languages that are not compiled. So, scripting languages fall under the second category, as these are not compiled and directly interpreted. In interpretation, the code is executed line by line. Accordingly, the output is given, whereas, in the compiler, the whole program gets executed in a single scan, undergoes different checks, and gives the report of errors accordingly. An interpreter executes the program by translating the statements into a series of one or more subroutines. After that, they are translated into another language, machine code that the machine can understand. A compiler first translates the code written in a high-level language to a lower-level language, and after that, the scanning of code starts. The executable made after the compilation is also specific to the machine. If we have written a code for windows OS, the executable will only work on windows, not on Mac.
Scripting languages can be used for different types of functions. The code written using a scripting language is called ‘scripts.’ Scripts are used in many places, both on the internet and off the internet. Scripts are used in server-side and client-side scripting when using on the internet, and when considering offline uses, scripts are used in system administration. Scripting languages are also used in the gaming and multimedia field. Many games use scripts to create a new environment in the games, which is a kind of fixed task that needs to be repeated for all the users. Also, scripts are used to create extensions in games, and similar to games, scripting also helps create extensions for web browsers. Sometimes scripts are used to do some tasks on windows command prompt, sometimes on UNIX terminal. Scripts make automated and repeated tasks very easy.
Some of the scripting languages with their utilities are:
· Bash: this is a scripting language and works with Linux OS. Bash scripts are easier to code than many other scripts written in different languages. Bash scripting is a handy skill for system administrators, especially those working with Linux systems. The cybersecurity field also sees great usage of bash scripting.
· Ruby: This language is a prevalent language among developers. Although it is in the industry for a long time, ruby’s popularity is still maintained due to its flexibility; it allows for great software with innovative concepts. This language is mainly used for web development.
· Python: Python is a free, open-source, and easy to learn and use language, but it has applications in many fields. Actually, python can be used to accomplish almost all the tasks related to computers. Supports both the object-oriented and procedural oriented programming style. This language has always been the trending one between budding computer programmers.
· Perl: This is a scripting language with different and innovative features that maintains the language’s uniqueness. This language can be found on both windows as well as Linux servers. Perl is suited to manage some very high traffic websites.
Now, let us get in detail about some of the most used scripting languages:
Shell Scripting or Bash Scripting
The shell script is a computer program that can run on a UNIX/Linux shell. The shell could be any one of these many: bourne shell, c shell, Korn shell, gnu bourne-again shell. Shell is a command-line interpreter and generally used to execute the shell scripts that usually do file manipulation, variable setting, program execution, installing programs, printing jobs, and almost anything. Bash is basically an application used to execute and run the applications installed on the system. Bash is the command that gets executed automatically when opening a terminal, so there is no use to execute it explicitly. Then we give commands to bash regarding an application, and if that application is installed, bash executes it. The writing of code on a terminal giving a series of commands to the bash is known as bash scripting or, more generally, shell scripting. We can write codes directly on bash or write a complete series of code in a file and then provide it to the execution bash. That file would be called a script. Bash scripts usually have an extension of .sh. Bash is like an interface to the whole of UNIX/Linux systems. Bash can be used to access almost anything, from system files to user files, applications, environment variables and system, and user data. Almost everything on Linux goes on bash shell, so technically, all those things could be scripted through bash.
There are two types of scripting languages about the web: server-side and client-side. Let us discuss them a little. A server-side scripting language runs on the server while a client-side scripting language runs on the client’s web browser or any other application accessing the web. The client-side scripts are viewable by all; a person can see all of the client-side scripting done in a webpage just by looking into the source code. The server-side scripts are not visible to the public. Only the person sitting on the server-side can view those source codes. Client-side scripts are faster to load and thus gives less pressure on the server. Client-side scripting enables the programmers to take care of the web page’s look and feel on the client side itself. All those are not dependent on the server-side. The server-side scripts focus on how to send the data faster, manage data, resolve errors, and other stuff affecting the efficiency.
Windows Batch Scripting
Scripting in windows is done in the command prompt. Also, Powershell has been introduced with recent versions of windows, which makes scripting even easier. Powershell supports many commands used in Linux shells, which are more familiar to most operating system developers. We call scripting on windows, just like we call Bash scripting for scripting in Linux. A batch script is used to automate the command sequences, which are used repetitively. Some features of batch script are: it can read inputs from users, has conditional control structures, supports regular expressions, supports data structures like arrays, can use the concept of functions, can also integrate other programming languages like Perl. Batch scripts are stored in text files, and this file is given to the windows shell – command prompt or Powershell for execution. They usually have extensions of .bat or .cmd.
Some of the server side scripting languages are:
· PHP: It is one of the most popular server-side scripting languages and has been in the industry for quite a long time. PHP is fast, flexible, and pragmatic. From simple blogs to complex websites, all are using PHP to date. This language is especially suited to web development. It is an acronym used for ‘hypertext preprocessor.’ PHP can support a wide range of databases, work on various platforms, and be compatible with most of the servers used today. It can be used to create, open, edit, delete files on the server. Can collect data, send/receive cookies and encrypt data.
· ASP.NET: It is an open-source web framework created by Microsoft to build modern web applications and services. NET. It works cross-platform on Windows, Linux, macOS. Along with web apps, this language is also used to create APIs for browsers and mobiles, providing real-time communication between clients and servers and the creation of microservices. .Net was already a platform made of tools, programming languages, and libraries to build many applications. ASP.Net only extends that feature of .Net to the creation of web apps.
· Java: scripting languages can be compiled into Java bytecode that can be executed on Java Virtual Machine (JVM). Java Specification Request(JSR) is used to address the integration of Java and scripting language. It defines a standard framework and application programming interface(API) to embed the scripts in Java applications. Java Server Pages(JSP) is an extension of Java Servlet technology that is platform-independent and pure Java server-side modules that can fit in the webserver framework and extend web server capabilities with a minimal load.
· Ruby: This is a dynamic open-source programming language whose focus is on simplicity and productivity. Ruby also has a very elegant syntax, which makes writing and reading codes in Ruby very efficient. Ruby sees everything within its code as an object. It is also very flexible that more parts can be added to it and unnecessary be removed according to the coder.
· Perl: It is a competent, resourceful language, packed with resources. It is an ancient language that has been evolving for 30 years. It supports many platforms and is suitable for both SDLC models – rapid prototyping and large-scale development projects. It supports both the concepts of object-oriented and procedural oriented programming. A large number of open-source modules are available for Perl from its large community. Perl also provides an interface with C/C++ and supports integration with many databases.
· Python: A swift, powerful, beginner-friendly, and multipurpose language. Python can easily be used for many tasks like database access, network programming, server-side scripting, and software/game development. Python is open-source and enjoys a huge pool of open source contributors, making the python repository great. Although being a scripting language, Python provides an object-oriented approach. In the path of automation, python is leading every other language.
Some of the client side scripting languages are:
· HTML: Hypertext Markup Language used to design the structure of web pages. HTML5 is the latest of the HTML. It provides default functionality for many of the features which previously required third-party software and extensions.
· CSS: It is used to give style to the webpage structure already built by HTML. It describes how a web page should look to the user. Majorly concerned with the UI.
Now we know a lot about what scripting language is, the different types of scripting languages, and what they are used mainly. Now let’s talk about the pros and cons of scripting language.
- It is easier to learn a scripting language than other categories of programming language. To learn and code in a scripting language, people generally do not need to know the technology they are working upon. Like if we need to learn client-side or server-side languages, the web’s knowledge is not required in-depth, though a little knowledge is a must.
- Scripting languages have minimal use of data structures and variables, so the editing is also easy. One doesn’t need to check the whole code for any errors in the usage of functions, data structures, techniques.
- Scripts always help add great visuals to the webpages, which makes the user experience even better. Modern web pages really need scripting languages to enhance the interface, including font, background, grid, foreground, etc.
- There are lots of different libraries that come in the package itself for different scripting languages. These libraries contain some predefined functions that help create modern applications in web browsers that give greater features and UI than the other programming languages.
- There is no requirement for the compilation of scripts; they are directly executed in runtime. This feature makes scripting languages fast, although sometimes there is a need for compilation also.
- Scripts written can easily be transferred from a system to another cause they are actually just a text file with some codes/statements written on it.
- Scripts are also used to build prototypes of large programs, which saves the hassle and time to test the original project.
- Writing scripts are totally free. There is no need to purchase a separate IDE for writing scripts or purchase any packages.
- Each operating system comes with a built-in scheduler, which allows us to run scripts. So, there is no need for installing or even a runtime environment separately for running scripts.
- Scripts are very useful to do some repetitive tasks on the system. Tasks like creation, deletion, edit, move, copy, etc. are some of the tasks which are repeated very frequently and scripts written for such tasks make the job easier.
- Scripts can be simple, and they can also be complex. Simple scripts are easy to write, but writing complex scripts is where the trouble begins. Such scripts take a lot of time to create and test.
- Scripts are used to manage regularly. There are a lot of scripts running in an organization on different systems. They all have to be recorded somewhere securely so that if there is some fault in some action, the problem could be traced using the record showing what script executed when.
- Scripts are generally written casually on a simple text editor. Like other programming languages, they do not contain a standard which to follow while writing the code. Also, there is no proper documentation for scripts. These things make it hard to read and understand the scripts written by other developers.
- Scripting languages do not have the capability to manage and schedule jobs; still, they are mostly required to accomplish such things. Using scripts for such tasks also reduces the user interaction with the system.
- Scripting languages lack the feature of alerting and reporting. There are no notification features when, e.g., an error occurred, request not completed, file not open, reached the end of the line. Also, they do not provide good auditing features, making it difficult to log the details.