Two things:

(1) Perl is specifically designed so that a program “just works, even on Windows.” Take that program to a Linux box and ... without source-code changes ... it still works. Therefore, a consistent nomenclature is used, regardless of the peculiarities of the host system:

• Forward slashes are used in file paths (and module paths).
• Backward slashes are used to indicate character escapes.
• There is a rich set of File:: modules (and the like) ... standard, and in CPAN ... which are designed to “insulate” your program from environment-specific concerns. If you want a file-path that “just works,” even if you move your app from Linux to Windows ... you got it.

  (2) When you use a module, the various subs in it are not automatically “exported” from it. (The module author can of course specify that it should be so, and you can specify exactly what you do want to export... that's why you sometimes see a list of names on a use statement.)

  In your specific case, the documentation in perldoc File::Basename clearly shows (in its SYNOPSIS) that by default the symbol basename will be exported. You seem to be using the exported routine correctly. But as you move forward with your learning of modules, you'll need to be familiar with (and to understand the reasoning for), idioms like these:

  • use File::Basename qw/basename/;
  • $foo = File::Basename::basename($bar);