You can print to your standard output like this:

print “Hello, World!n”;

But the print command can also accept a file-handle, which we generate when opening a file.

open FILE, ‘>file.html’;

Immediately following the “open” command is the file-handle “FILE”, which is a variable that perl uses to keep track of open files. You can name this anything you want, but you’ll always need a comma between the file-handle and the file. The > at the beginning tells perl the file is writable.

With an open file-handle, you can now print directly to that file:

print FILE “Hello, World!n”;

Of course, you can also write scalar variables to the file:

$string = “Hello, World!n”;
print FILE $string;

These two commands are the foundations for generating dynamic web pages in perl. Using them, you can write your html to a file, along with the data your perl program processes.

Today, sites like Amazon.com, bbc.co.uk, Priceline.com, Craigslist and IMDb use Perl. It has even been used for other tasks like creating computer games, flight simulators and automated web photo galleries.

But how can you learn it?

There are several ways to start.

There are many web resources to use, starting with learn.perl.org. This site gives you a beginner’s breakdown of Perl, including directions on how to install it, basic programming practices, frequently asked questions and more. According to the website, there are also more than 107,000 modules ready for you to use. Perl modules are a set of related functions in a library file, designed to be reusable by other modules or programs.

The good news is that if you want to use Perl, it is compatible with any operating system – Unix, Windows, Apple – and with any Internet connection – cable, DSL or high speed satellite internet service.

The advantage of using Perl programming to implement external web services is that it is compatible with many programs that offer quick and practical access to Web information, and serves as a springboard for communication technology protocol on the Internet. Understandably, it currently is the most popular script language for web programmers hands down.

Perl is used for graphics programming, system administration, network programming, finance, bioinformatics, and other applications. its flexibility and power.[10] It is also referred to as the “duct tape that holds the Internet together. Perl is designed to make efficient use of expensive computer-programmers.

Perl has many features that ease the task of the programmer at the expense of greater CPU and memory requirements. These include automatic memory management; dynamic typing; strings, lists, and hashes; regular expressions; introspection; and an eval() function. Perl follows the theory of “no built-in limits”,[35] an idea similar to the Zero One Infinity rule.

Functional decomposition allows an individual to look at each aspect of a program individually. It can be extremely difficult to understand the overall function of a large program or application. By breaking down a program into its functional components, it’s possible to improve one’s understanding of its use.

One of the best ways to perform functional decomposition is through ‘breaking’ a program. For each function in a program, try changing a small piece of code. After each change, run the application. By breaking specific parts of a program in a pattern, it’s possible to understand what overall role they have in a program. In addition, this can be a great way to improve one’s programming skills.

For Loop
This is your typical for loop that iterates using a counter.
Eg) for ($roomnumber=1;$roomnumber<=100;$roomnumber++) { ... }

While Loop

This loop evaluates a condition and ONLY executes the commands within the loop IF a certain condition is met BEFORE entering the loop.Didn’t catch that? ‘http://nedbatchelder.com/text/iter.html’>This explains it. it is possible for the loop to not be executed at all, if the condition isn’t even met at the outset.

Eg) while ($lights eq “off”) { … }

Foreach Loop

If you have an array of scalar values, this loop will iterate through each element (which gets assigned to a local variable for use within the for loop) and execute the commands within the loop, until the last array element has been reached.

Eg) foreach $dayofweek (@weekdays) { print “$dayofweek\n”; }

Until Loop

This loop is similar to the While loop, except that the condition is evaluated AFTER each loop iteration. Therefore, this type of loop is ALWAYS executed a MINIMUM of one time.

Eg) until ($lights eq “on”) { … }

One such example is Perl’s ability to operate on the most recent variable name that was invoked, without having to reference it again, using the $_ symbol.

Another example would be Perl’s ability to write simple if or unless statements as one line of code. For example:
print “Good morning” if ($timeofday eq “AM”);

Pattern matching also an extremely effective way to keep your coding to a minimum. You can use pattern matching evaluations as a boolean expression nested within an ‘if’ statement. You can even perform variable assignments and even pattern matching substitutions within if statements as well.

Breaking your code into modular subroutines also helps to make your code more efficient and manageable.

As far as formatting your code for readability, there are many free text editors that you can use to keep your code formatted properly with indentations and to keep your open and close brackets properly aligned in uniformly indented columns as well.

Perl is extremely versatile and flexible. When coded properly, it can be optimized quite well.

The launch PERL took place around December 18, 1987 introduced as a Practical Extraction Reporting Language (PERL.) Larry Wall (Wall) was the author of the programming language working at NASA Jet Propulsion Laboratories. During this time, Wall was also working with UNIX creating utilities that would expand the range of use for the operating system. PERL interfaced with the UNIX operating system to result in a powerful expression engine that would later become the kernel for all PERL programming. PERL is the oldest, and conventionally more powerful than most programming languages.Check out this link here. There are to date many different versions and modifications of PERL!

Modern PERL

PERL programs are native to UNIX and LINUX operating systems used by some of the wealthiest corporations controlling all online operations. While PERL programs can run on MSOS, the OS must be generally adapted to accept PERL programs. Understanding PERL requires the understanding the history of PERL in detail. Most users that follow this track are not only able to grasp PERL programming, but, also programming of low-level operations. The more understanding an individual has of PERL broadens the individual’s ability to solve logical and analytical problems. Search the web to locate PERL resources!