Beginners Guide to CGI in Perl
by Nathan Poole
Why learn Perl?
Perl (Practical Extraction and Report Language) is probably the most widely used programming language for CGI. To start you off learning Perl, I feel obligated to give credit where credit is due. First off, to Larry Wall for creating Perl itself. Secondly, thanks must be given to Randal L. Schwartz and Tom Christiansen (in no particular order!) for writing some of the best Perl documentation ever published.
First off, to program in Perl I suppose it would be a smart idea to download Perl itself. If you're running Windows95/98/NT you run Perl through MS-DOS. First, for Win32 users, click the link below to download Perl for Win32 by ActiveState.
Pw32i316.exe (1,511 KB) (Perl for Win32 Intel/x86 binary)
After you've download the preceding file, extract it on your machine. It creates the directory C:\Perl and that's all there is to it. You've now installed Perl. Now you'll need to reboot your machine.
Discussed is the following, think of it as 4 easy lessons. There are hundreds of Perl commands, we're going to use 4 to begin with, and we're going to make a program with them.
- Perl Path
- Defining Variables
- Comparing with if statements
When a server installs Perl on their machine, it's given a directory to be stored in. Just like your Perl program was installed in C:\Perl, their Perl would most likely go in a directory /usr/bin/perl. You refer to this so your program knows where to find Perl. This obviously is the first thing in your program. Since I'm assuming everyone using this tutorial is on Windows, we don't need to define these when we're using your Windows Perl, but we will just to get you in the habit. At the top of your program you'll want to type:
This is where Perl is usually installed on a server. If you seem to be having problems when we jump into CGI, check the troubleshooting section of this article and there you can find out how to check your perl path.