Perl Basic Syntax

Perl Basics – Part 2

Perl Course

Foreword: In this part of the series, I give you the basic syntax of Perl.

By: Chrysanthus Date Published: 29 Mar 2015

Introduction

This is part 2 of my series, Perl Basics. In this part of the series, I give you the basic syntax of Perl. As I said in the previous part, ActivePerl and Perl are the same in very many ways. I use ActivePerl for the code samples. You can still use a different Perl for the code samples, but precede any code sample (script) with something like, #!/usr/bin/perl ; the corresponding Perl manual should tell you exactly what to type. With Windows’ Perl, which is ActivePerl, you do not need that preceding line. You should have read the previous part of the series before reaching here, as this is a continuation.

Statement
A statement in Perl is a short piece of code that ends with a semicolon. An example is:

        print "Hello World!\n";

This statement displays or prints "Hello World!" without the quotes, at the console.

Comments
You should have comments in your code. Comments are not executed. Comments are to remind you later of why you typed a particular piece of code. In Perl, you generally have a comment in a single line; something like:

        #This is a comment.

You begin each comment with the hash, # character. Your code is executed by the interpreter to perform a task, such as to print a piece of text. When the interpreter sees the # character, it ignores everything that is on its right. That is, it does not execute what is on the right of the # character.

Comment Example
Type the following in a blank page of a text editor:

use strict;

#Talking about a man.
print "I am a man.\n";
#Talking about a boy.
print "He is a boy.\n";

Save the file as comment.pl in the root directory (C:\).
Start the console and use the cd c:\ command to go to the root, C:\> prompt. Then, type the following command and press the Enter Key:

    comment.pl

The following should be printed:

I am a man.
He is a boy.

In the comment.pl script, you have two comments, which are “#Talking about a man.” and “#Talking about a boy.”. Since these are comments in the Perl code, they do not appear at the console. The Perl interpreter in the computer does not send them to the console.

String
If you see any text in double or single quotes in Perl code, that text is called a string. In this and the previous part of the series, you have seen strings only in double quotes. You have not yet seen strings in single quotes. You will see that soon.

Let us end here for this part of the series. We continue in the next part.

Chrys

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