The files you created in Chapter 12 were generally in the same place as your program. But modern operating systems let you organize files into directories. Perl lets you manipulate these directories directly, in ways that are even fairly portable from one operating system to another.
Perl tries very hard to act the same no matter which system it runs
on. Despite that, this chapter certainly shows Perl’s preference toward its
Unix history. If you are using Windows, you should look at the
Win32 distribution. Those modules provide hooks to
the Win32 API.
Your program runs with a working directory. This is the default directory for everything your program does.
Cwd module (part of the Standard Library), you can see what that
directory is. Try this program, which we’ll call show_my_cwd:
use v5.10; use Cwd; say "The current working directory is ", getcwd();
This should be the same directory that you’d get if you ran pwd in the Unix shell or cd (with no argument) in the Windows command shell. While you’re practicing Perl with this book, you’re most likely working in the same directory that holds your program.
When you open a file using a relative path (one that does not give the complete path from the top of the filesystem tree), Perl interprets that relative path starting at the current directory. Say that your current working directory is /home/fred. When you run this line of code to read a file, Perl looks for /home/fred/relative/path.txt ...