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 ::   Intro to Perl/CGI and HTML Forms
 ::   Intro to Windows Perl
 ::   Intro to Perl 5
 ::   Intro to Perl
 ::   Intro to Perl Taint mode
 ::   Sherlock Holmes and the Case of the Broken CGI Script
 ::   Writing COM Components in Perl

Java tutorials
 ::   Intro to Java
 ::   Cross Browser Java

Misc technical tutorials
 ::   Intro to The Web Application Development Environment
 ::   Introduction to XML
 ::   Intro to Web Design
 ::   Intro to Web Security
 ::   Databases for Web Developers
 ::   UNIX for Web Developers
 ::   Intro to Adobe Photoshop
 ::   Web Programming 101
 ::   Introduction to Microsoft DNA

Misc non-technical tutorials
 ::   Misc Technopreneurship Docs
 ::   What is a Webmaster?
 ::   What is the open source business model?
 ::   Technical writing
 ::   Small and mid-sized businesses on the Web

Offsite tutorials
 ::   ISAPI Perl Primer
 ::   Serving up web server basics
 ::   Introduction to Java (Parts 1 and 2) in Slovak


introduction to web programming
Reading a File Line by Line  
An often used technique in CGI scripts for the manipulation of files is the reading of each line of a file. Perhaps we want to check each line for a keyword, or find every occurrence of some marker tag on a line and replace it with some other string. This process is done using a while loop as discussed previously. Consider this routine that will print out every line in a address file:

    open (ADDRESSES, "address.dat") ||
         &CgiDie ("Cannot open address.dat");
         while (<ADDRESSES>)
           print "$_";
    close (ADDRESSES);

Thus, the script would print out every line in the file address.dat because "$_" is Perl's special name for "the current line" in this case.

You can also manipulate the "$_" variable in other ways such as applying pattern matching on it or adding it to an array.

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