Writing Your First REXX Program: A Complete Beginner’s Guide to Getting Started with REXX

Hello fellow REXX enthusiasts! In this blog post, I’ll introduce you to

Writing Your First REXX Program – one of the most fundamental and essential concepts in REXX programming: writing your first REXX program. Writing a program in REXX is simple yet powerful, allowing you to create dynamic and interactive scripts. Whether you’re new to programming or just starting with REXX, understanding how to write a basic program is a key step in your journey. In this post, we’ll explore the basic structure of a REXX program, how to get started, and the important components you’ll need to create your first script. By the end of this guide, you’ll be ready to dive into REXX programming with confidence. Let’s get started!

Introduction to Writing Your First REXX Program

Welcome to the world of REXX programming! In this guide, we will walk you through writing your very first REXX program. REXX is a simple yet powerful language, ideal for beginners looking to get started with scripting. This tutorial will introduce you to the basic structure of a REXX program and how to write and execute your first script. You’ll learn the key concepts, such as variables, commands, and syntax, that form the foundation of every REXX program. By the end, you’ll have a solid understanding of how to create your own REXX programs. Let’s dive in and start coding!

If you’re new to REXX programming and want to get started with your first program, this guide will walk you through the essential steps. You’ll learn the basics of the REXX language, understand its syntax and structure, and write your first program step-by-step. By the end of this guide, you’ll have a working knowledge of how to create a simple REXX script and execute it. Let’s dive into the process!

What is REXX?

REXX (Restructured Extended Executor) is an easy-to-learn, high-level programming language designed for scripting and automation tasks. It’s simple, versatile, and used for a variety of applications, including data manipulation, text processing, and system administration tasks. REXX is primarily used for writing small scripts or programs to automate repetitive tasks.

Setting Up REXX

Before writing your first REXX program, you need to install a REXX interpreter. Some popular options include:

• Regina REXX (Windows/Linux/Mac)
• Open Object REXX (ooREXX) (Windows/Linux)

You can install Regina REXX from Regina REXX official website, or follow installation instructions specific to your operating system. After installation, you can start writing and running REXX programs.

Writing Your First REXX Program

Now that you have everything set up, let’s write a simple “Hello, World!” program in REXX. This is the most basic program for any beginner learning a new language.

Example Code:

/* Hello World in REXX */

say "Hello, World!"

• /* Hello World in REXX */: This is a comment. Anything between /* and */ is ignored by the interpreter and used for code documentation or explanation.
• say "Hello, World!": The say command is used to print text to the screen. This command is simpler than print in many other programming languages and is used frequently in REXX for output.

Running Your First REXX Program

After writing the program, save it as hello.rexx (or any other name with .rexx extension). Now, you need to run it using the REXX interpreter.

How to Run?

• In Windows: Open the command prompt, navigate to the directory where your hello.rexx file is saved, and run the command

rexx hello.rexx

• In Linux/Mac: Open a terminal, navigate to the folder where your hello.rexx file is saved, and run the command

rexx hello.rexx

You should see the following output

Hello, World!

Understanding Variables and Data Types in REXX

In REXX, you don’t need to explicitly declare variable types. It’s dynamically typed, which means you can store any type of data in a variable (such as a number, string, or list).

Example Code:

/* Variable Example in REXX */

name = "Alice"   /* String variable */
age = 25         /* Numeric variable */

say "Name: " name
say "Age: " age

• name = "Alice": This creates a variable name and assigns it a string value.
• age = 25: This creates a variable age and assigns it a numeric value.
• The say command prints the value of the variable to the screen.

When run, the output will be:

Name: Alice
Age: 25

Basic Control Structures in REXX

You can use basic control structures like loops and conditionals in REXX to create more dynamic programs.

Example Code (If-Else Statement):

/* If-Else Example in REXX */

age = 18

if age >= 18 then
    say "You are an adult."
else
    say "You are a minor."

• The if statement checks if the condition is true. If age >= 18, it will print "You are an adult.
• "Otherwise, it will print "You are a minor.

Loops in REXX

REXX supports loops, which are essential for repetitive tasks. A common loop in REXX is the do loop.

Example Code (Do Loop)

/* Do Loop Example in REXX */

do i = 1 to 5
    say "Count: " i
end

• do i = 1 to 5: This initiates a loop where i will go from 1 to 5.
• say "Count: " i: Inside the loop, it prints the current value of i.
• The end keyword signals the end of the loop.

The output will be

Count: 1
Count: 2
Count: 3
Count: 4
Count: 5

Conclusion

Congratulations! You’ve just written your first REXX program and learned the basics of variables, control structures, and loops. This guide is just the beginning of your REXX programming journey. As you continue to explore, you’ll be able to create more complex programs, automate tasks, and manipulate data with ease. Keep practicing, experiment with more REXX features, and don’t hesitate to dive deeper into its powerful capabilities