To run a perl script with warnings, type -w with the shebang as in
#!/usr/bin/perl -w
print “Content-type: text/html\n\n”;
print “Hello World\n”;

Check if you have the following line in the program
print “Content-type: text/html\n\n”;
This will output the text to the browser from the server.

Print error messages to the browser using
use CGI::Carp qw(fatalsToBrowser);

The other way is to use the print command to debug your program.

Common error messages
» The specified CGI application misbehaved by not returning a complete set of HTTP headers.
» Can’t locate missing-file.pm in @INC (@INC contains: ….. )

Perl is a scripting language. It is often misconceived to be the same as CGI, as Perl was the popular language at the time when CGI gained momentum in the web world.

CGI can refer to a “scripting language” which gets interpreted when calls to a page from the webserver is being made. It can be referred as a “program“, when it gets executed on the webserver to have access to resources with hard coded paths other programs when a call from a web page happens.

In short, all Web applications built using ASP/PHP/Python/Perl speaks through the channel – CGI.

I prefer ActiveState download for a beginner to have a Perl installation with compiled libraries for immediate execution of various Perl programs. You can grab a copy based on your OS from

http://www.activestate.com/activeperl/downloads/

Download the x86 .deb file for easy installation of ActivePerl on Ubuntu. If you have downloaded it to your /tmp location then you can unpackage the download by executing the below command

$ sudo dpkg -i /tmp/name-of-active-perl.deb

Normally it gets installed in the directory /opt. You can move the directory to the location of your choice.

Check your path settings by
$ echo $PATH

If there were previous installation of perl, you need to modify the path setting so that the setting to ActivePerl location comes prior to all other perl locations.

Task: List installed perl module

To display the list enter the following command:
$ instmodsh

How to set Perl path for libraries?

export PATH=$PATH:/home/YourUserName/bin

Note that the path separator here is “:” (semi-colon)

There might be a possibility that an edit of .bashrc file may become corrupted. If it happened to you, then you may not be able to execute most of the commands on linux prompt.

The solution for it is to reset the path settings in order for bash file to identify what the commands are in that shell.

Execute the below command to reset Ubuntu path settings

$export PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games

Ensure that there is no “space” around equal to sign in the path settings.

Visit activestate.com website to get more installation related info
http://docs.activestate.com/activeperl/5.10/install.html