PERL Scripting Training in Coimbatore

Where is Perl used?

The power of Perl can be implemented in many fields. The most popular use of Perl is in Web development. Perl is also used to automate many tasks in the Web servers, and other administration jobs, it can automatically generate emails and clean up systems. Perl is still used for its original purpose i.e. extracting data and generating reports. It can produce reports on resource use and check for security issues in a network. Due to this reason, Perl has become a popular language used in web development, networking and bioinformatics too. Apart from all this Perl can also be used for CGI programming.

Perl can also be utilized for image creation & manipulation. Apart from that networking via telnet, FTP, etc., Graphical User Interface creation, VLSI electronics & to create mail filters to reduce spamming practices are some use cases of Perl

Perl is also known for implementation of OOP (object oriented programming) practices and supports all forms of inheritance (simple, multiple & diamond), polymorphism and encapsulation. Perl is flexible enough to support Procedural as well as OOP practices simultaneously. Perl also has extra modules which permit you to write or use/reuse code written in Python, PHP, PDL, TCL, Octave, Java, C, C++, Basic, Ruby  in your Perl script. This means that you can combine Perl with these extra programming languages rather rewriting existing code.

Why use Perl?

• It is true that there are other programming languages that can be used to do all the stuff that has been stated above, then why should you specifically use Perl? 
• Perl is very easy to learn, especially if you have a background in computer programming.
• Perl was designed to be easy for humans to write and understand rather than making it easy for processing by computers. It uses regular expressions.
• Its natural style of language is different from other programming languages that use specific grammar and syntaxes; therefore, Perl is very flexible and doesn't impose on you any particular way of thinking out a solution or a problem. 
• Perl is extremely portable. It can run on any operating system that has Perl interpreter installed, so it is platform independent.
• All Linux Operating Systems come installed with Perl, so you can start Perl coding in Linux out of the box.
• PERL in which the code changes with the flavor of Linux distribution being used, making it less and less portable Small specific tasks in Perl becomes very easy and quick.

The Benefits of Using Perl

Perl has many advantages as a general-purpose scripting language. These benefits include its generous licensing (it's free), its interpreted nature, the fact that Perl is available for most platforms, and more. The following sections detail some of the benefits of this excellent language.

Cost and Licensing

First, Perl is generally available on most server platforms, including the following:

• Most UNIX variants
• MS-DOS
• Windows NT
• Windows 95
• OS/2
• Macintosh

Perl also has the distinct advantage of being "low cost." It is distributed free of charge or, at most, for a small copying charge. Actually, Perl is distributed under the GNU "copyleft," which means that if you can execute Perl on your system, you should have access to the source of Perl for no additional charge. (Actually, a small copying charge might be imposed.) Perl may also be distributed under the "artistic license," which some people find less threatening than the copyleft.

Availability

Perl is readily available from many sources, including any comp.sources.unix archive or CPAN site. If you don't have Perl on your server or development machine, it is easy to obtain either as source code or precompiled binaries for many platforms. For those not on the Internet, Perl is available via anonymous Uucp from both uunet and osu-cis. Perl is often distributed with CD collections of utilities for UNIX platforms.

Easy to Use

Above all, Perl is a language in which you can do things. There are usually several ways to accomplish the same task. Although some techniques are more efficient with system resources than others, users can generally select the technique that is easier for them to use (and maintain/enhance in the future) and go with it.

The ease of use and completeness make Perl appropriate for quick-and-dirty, one-time utilities as well as structured, complex applications.

Efficient

Perl is a straight-line language, which means that simple programs do not have to deal with complex formatting or function/procedure or object/method structures to accomplish their task. As a simple example, let's pay homage to programming texts 

Language Capabilities

Perl is optimized for text processing and, therefore, is very efficient at many tasks required of system administrators and application developers. Many of the files used in UNIX systems administration are plain text files. Selecting records, processing the selected records, and reporting exceptions are the heart of many tasks performed in UNIX administration.

In the current versions of Perl, the language also includes much additional functionality, making it appropriate for tasks such as processing socket calls, embedding in programs written in C, and maintaining POSIX-compliant systems.

Integration with C

Perl can access C libraries to take advantage of much of the code written for this popular language. Utilities included with Perl distributions enable you to convert the headers for these C libraries into their Perl equivalents

What Can Perl Do?

Perl is most commonly used to develop system administration tools. But it has also gained enormous popularity on the Internet. Perl can be, and is, used to develop many Internet applications and their supporting utility applications. The following sections describe some applications of Perl in systems administration and on the Internet.

UNIX System Maintenance

As mentioned before, Perl can perform the work of several other tools, and usually in less time. It is particularly adept at processing the text files typically used as configuration files.

CGI Scripts

Perl is one of the most popular languages for creating CGI applications. There are literally thousands of examples of dynamic CGI programming in Perl. Perl can be used to create dynamic Web pages that can change depending on factors such as which visitor is viewing them.

One of the most common uses of Perl on the Internet is to process form input. Perl is especially adept at this chore because most of that input is textual-Perl's strength.

Mail Processing

Another popular use of Perl is for the automated processing of Internet e-mail. Perl scripts have been used to filter mail based on address or content. Perl scripts have also been written to automate mailing lists. One of the most popular of these programs is Majordomo.

I personally have written a Perl script to automate my "What's New?" Web page. This script processes mail messages and adds them to my "What's New?" page. It also removes the entries from the page after they have been there for a certain length of time.

Automating Web Site Maintenance

Perl can be used to automate the maintenance of Web sites. Because Web pages are little more than text files in a specific format, Perl is particularly adept at processing them. Perl's socket capability can also be used to contact other sites and request information using HTTP. There has even been a Web server written in Perl.

In order to check the links on a site, a Perl program must parse the sites pages starting with the main page, extract the URLs, and determine whether these URLs are still active.

Automating File Retrieval

There are several FTP clients written in Perl. Perl can be used to automate file retrieval via FTP. Again, this combines the socket capability of Perl with its text-processing capability.