Perl Basics

Starting Perl
Typically, perl is used to interpret a script. You can run a script explicitly with perl (the % is your command prompt)

% perl scriptname

or

% cat scriptname | perl

That isn't convenient enough, since you'd rather not have to distinguish what is a real compiled program and what is a script. Therefore, UNIX shells have a shortcut. If a text file is executable, and the first line is of the form

#!program [optional program arguments]

the shell executes

program [optional program arguments] scriptname

Note: While there is some leading whitespace to offset the code examples, all examples should not use the first - especially this example of the shell shortcut.
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Example
To start off our program, edit the file mailform, add the first line:

#!/usr/local/bin/perl

(or whatever the location of your perl binary is), save, exit the editor, and make the program executable:

% chmod +x mailform

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Here's some information that applies to all of perl.
Perl is free form - whitespace doesn't matter. Most people like to use liberal indentation, but you could write all on one line, if you're a masochist.
All perl statements end in a ; (semicolon), like C.
Comments
begin with # (pound sign)
everything after the #, and up to the end of the line is ignored.
the # needn't be at the beginning of the line.
There is no way to comment out blocks of code other than putting a # at the beginning of each line. It's a convention taken from the shell utilities, sorry C folks.{damn}

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Example
Now our program looks like this:

#!/usr/local/bin/perl
# mailform - a simple CGI program to email the contents of an HTML
# form to a specified user.
#
# kolij badman
# kolij@osr.nitto
# September, 2003

-kolij-