A First Perl CGI Script

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A First Perl CGI Script

Let us now look at how we write our first perl program that will be used as a CGI script.

We will learn three main things in here:

The format of Perl CGI program
Now to output in HTML data format

Format of a Perl program

Every Perl program MUST obey the following format:

A first line consisting of:
```
#!/usr/local/bin/perl
```
The rest of the program consisting of legal Perl syntax and commands
For CGI the Perl output must be in HTML -- this is where Perl is really handy.

Strictly speaking the first line is only required for running Perl programs on UNIX machines. Since that is the intended destination of most of our Perl scripts. It is a good idea to make this the first line of every perl program.

Output from Perl

To output from a Perl script you use the print statement:

The first line of our CGI script must be ``Content-Type: text/html'' and the print statement must have 2 \n characters:
- One to terminate the current line, and
- The second to produce the require blank line between CGI header and data.

print "Content-Type: text/html\n\n";

Finally -- Our complete script

Recall that our Perl CGI script must output the header and HTML code and must begin with a special first line.

Our complete first (hello.pl) program (with nice comments) is a follows:

#!/usr/local/bin/perl
# hello.pl - My first CGI program

print "Content-Type: text/html\n\n";
# Note there is a newline between 
# this header and Data

# Simple HTML code follows

print "<html> <head>\n";
print "<title>Hello, world!</title>";
print "</head>\n";
print "<body>\n";
print "<h1>Hello, world!</h1>\n";
print "</body> </html>\n";

Next: Exectiion of CGI Programs Up: Beginning CGI Programming in Previous: CGI Script Output

dave@cs.cf.ac.uk