Perl was one of the first computer languages every written, through it's
years of existence the contributors of the language have made it one of
the the most robust and powerful languages there are. Perl is short
for Practical Extraction Report Language, because that's what it is.
It creates and extracts data on the fly with remarkable speed.
You will often times here the words Perl and
CGI together as if they're one and the same. It's safe to think
this, as CGI is a module built for Perl, the main difference is CGI is
typically OOP (object-oriented programming) while Perl itself usually
is not. CGI is short for Common Gateway Interface which is a great
name because it's Perl's interface to work on the web.
What does it do?
Since this is one of the fastest languages there are, this makes a great
report processing and retrieval language. You can parse hundreds
of thousands of lines of code from a text file in just a few seconds (I
typically can get around 80,000 lines returned in a fraction of a second).
Some very common uses for Perl/CGI: Data extraction,
encryption, contact forms, guest books, full e-commerce sites, web parsers
and web bots, search engines, image manipulation, security.
What can't it do?
It can do nearly anything you can think of when working in strictly
Perl on your own computer. You can create graphics, setup password
scripts, encrypt files, track users, etc. But on the web, it's only
limitation is the fact it's a server-side language.
This means that the content created using
Perl/CGI is not dynamic; all of it's work is done at the time the page
loads. This is unlike JavaScript which can have content change at
any given time. A simple example of this would be a contact form.
The fields can't be checked or verified on the page that just loaded,
the page has to reload or redirect before Perl/CGI can use this information.
What do I need?
If you want to run Perl scripts on your own computer and you're on Windows
or Mac, you'll need to download
Active State Perl. The link for this
can be found in Tutorials section, be sure to always download the latest
version. At the time of writing this article, the latest version
is 5.8.3.
To use CGI, you'll either need your own server
or a server hosted by another company online. Your server or web
host must allow CGI support. If it doesn't, you will not be able to use
web based Perl scripts. There are many free servers out there that
do allow CGI and nearly all paid hosts will. CGI is a standard which
makes finding a worthy host a much simpler task.
