The document discusses a presentation on CGI (Perl). It provides an introduction to CGI and CGI architecture, then discusses Perl including that it is a programming language developed in 1987, its basic syntax like variables and comments, datatypes like arrays and hashes, and provides a simple "Hello World" example program in Perl.

1. Presentation on CGI (Perl)
Presented By : Ishwor Panta
Roll No. : 13

2. Contents
 CGI Introduction
 CGI Architecture
 Perl Introduction
 Perl Basic Syntax
 Perl Datatypes
 Sample Program of Perl

3. What is CGI
 Protocol for executing scripts via web requests
 Rules and standards that define how the information is exchanged between
the web server and custom scripts
 Code called by HTTP server was referred to as the CGI script
 CGI applications are very powerful (accessing database, generate graphics,
hold telnet session )
 Protocol for generating dynamic web pages

4. CGI (Common Gateway Interface)
 Common
 Interaction with many OS.
 Gateway
 Provides way to gain access to different programs such as database
 Interface
 A method for interaction with web server

5. CGI Architecture
 HTTP protocol initiate connection on client machine
 Client machine exchanges information with web server
 Web server run server side script to access the dynamic content

6. Perl
 Perl is a programming language developed by Larry Wall
 Stands for Practical Extraction and Report Language
 Platform Independent
 Perl 1.0 was released in 1987
 Latest Perl version is 5.30.1
 Works with HTML, XHTML
 Perl database integration interface support third party databases

7. Basic Syntax
 Variables
 Variables are user defined words used to hold values
 Examples:
 $name = “Visit Nepal” ;
 $num = 10 ;
 @ages = ( 10, 21, 56, 20, 92) ;
 Expression
 Made up of variables and operators symbols
 Example:
 $x + $y

8. Basic Syntax
 Comments
 Useful information developer provide to understand source code
 Types
 Single line comments
 Start with hashtag symbol i.e. #

9. Basic Syntax
 Comments
 Multiline Comments
 Enclosed with “=“ and “=cut”

10. Datatypes in Perl
 Arrays
 Scalars
 Hashes
 Strings

11. Datatypes in Perl
 Arrays
 Variable that stores values of same data types
 To declare array in perl, we use @ symbol
 Example
 @number = ( 40, 55, 63, 17, 22, 68, 89, 97, 89)
 To access single element in array, we use $ sign as :
 $number[0]

12. Datatypes in Perl
 Scalars
 Single unit of data which can be integer number, float, a character, a string
 Example

13. Datatypes in Perl
 Hashes (Associative Arrays)
 Set of key-values pairs
 To declare Hash in Perl, we use ‘ % ’ sign
 To access particular value, we use ‘ $ ’ symbol which is followed by key in braces
 Example

14. Datatypes in Perl
 Strings
 Strings starts with $ sign and it can contain alphabets, numbers, special character
 Can contains single word, a group of words , paragraph
 Single or double quotes can be used
 Example

15. Hello World Program in Perl
 In Perl, basic program consists of the following steps of execution
 Step 1 : Transfer the file to Perl Interpreter
 Step 2 : Modules in Perl
 Step 3 : Use of print() of function

16. Hello World Program in Perl
 Output