acf5 Web Page and Perl CGI Setup

Here's how to set up HTML web pages and Perl CGIs which run on acf5.nyu.edu. This writeup is derived from Mark Meretzky's guide.

Home Page setup

Let's assume your NetID on acf5 is abc1234.

Step 1. Create a subdirectory of your abc1234 home directory named public_html. Make sure that it has an underscore, not a dash. Chmod the public_html directory to have the permissions rwxr-xr-x using the command chmod a+rx public_html

Step 2. Create a file named index.html in your public_html subdirectory. This will be your default WWW home page on acf5. Chmod the index.html file to have the permissions rw-r--r-- using the command chmod a+r index.html

The WWW URL of your home page is now http://acf5.nyu.edu/~abc1234

Perl CGI setup

Step 3. Create a subdirectory of your public_html directory named cgi-bin. Note that "cgi-bin" has a dash, while "public_html" has an underscore. Chmod the cgi-bin directory to have the permissions rwxr-xr-x using the command chmod a+rx cgi-bin

Step 4. Create a perl program in your cgi-bin directory. The program must:

  1. Have a #! (shebang) line as its first line which executes perl;
  2. Output two initial lines containing "Content-type: text/html" on the first line and a completely blank line as the second line. (Both lines are terminated by \n).
  3. Output the HTML for a web page.

Let's say you create hello.pl. It might look like this: 

#!/usr/bin/perl -w

# Output required CGI header

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

# Output text of my simple web page

print <<END_HTML;
<html>
<title>Hello world</title>
<body>
<h1>Hello, world</h1>
</body></html>
END_HTML

exit;
Step 5. Execute your perl script from the shell (command line). Run the command ./hello.pl. If if produces the header line Content-type: text/html, followed by a blank line, followed by your HTML output, then you are in good shape. If it does not execute, gets an error from perl, or does not produce the expected output, then you will need to review the above steps until your hello.pl CGI runs from the shell. If your perl CGI does not run from the command line, it will not run as a CGI web page. It is much easier to debug problems when working form the command line than when you try to run it from a web browser.

Step 6. Next, execute your perl script from a web browser. Enter this URL into your browser:

http://acf5.nyu.edu/cgi-bin/cgiwrap/~abc1234/hello.pl

If it does not run, go back to Step 5.

Step 7. Finally, put the following sentence in your index.html file: 

Click
<a href = "http://acf5.nyu.edu/cgi-bin/cgiwrap/~abc1234/hello.pl">here</a>
to run my Hello Perl CGI.