Learning Perl on Win32 Systems

Basic Concepts

A Perl program is a bunch of Perl statements and definitions thrown into a file. You can execute the file by invoking the Perl interpreter with the script name as an argument. You will often see a line

#
            !/usr/bin/perl

as the first line of a Perl script. This line is a bit of magic employed by UNIX-like operating systems to automatically execute interpreted languages with the correct command interpreter. This line is called a shebang line due to the first two characters: # is sometimes called sharp, and ! is sometimes called bang. This line normally won’t work for Perl-for-Win32 users,^[5] although it doesn’t hurt anything since Perl sees lines beginning with # as comments.

The invocation examples that follow assume that you have invoked the Windows NT command interpreter (cmd.exe) and are typing into a console window. You can run Perl scripts from the Explorer or the File Manager (assuming that you’ve associated the script extension with the Perl interpreter) by double-clicking on the script icon to launch it. Throughout this book, we’re going to be discussing standard output and input streams; these are generally assumed to be your console window.

We recommend naming scripts with a .plx extension. Traditionally, Perl modules have a .pm extension, and Perl libraries have a .pl extension. The ActiveState installer prompts you to associate .pl with the interpreter.

You can always execute a script by calling the Perl interpreter with the script as an argument:

> perl myscript.plx ...