Paths in Perl

[tachyon]

Different Operating Systems use different characters as their path separator when specifying directory and file paths:

foo/bar/baz    # *nix uses a /
foo\bar\baz    # Win32 uses a \
foo:bar:baz    # Mac OS 9 uses a :
foo/bar/baz    # Mac OS X uses a / (usually!)

In Perl you can generally just use a / as your path separator (except on Mac OS 9, thanks Hanamaki). Why? Because Perl will automagically convert the / to the correct path separator for the system it is running on! This means that coding Windows paths like this

$path = "\\foo\\bar\\baz";

is not required. You can just use this:

$path = "/foo/bar/baz";

and things will be fine. In fact using \\ can be problematic, but you probably already know that :-)

If you want to display the expected system delimiter to a user (ie hide the fact that you are using / internally) you can just do something like this:

my $perl_path = '/foo/bar/baz';
(my $win_path = $perl_path) =~ tr!/!\\!;
print "Perl still sees:  $perl_path\n";
print "But we can print: $win_path\n";

If you need to do lots of conversions just write a sub like this:

my $perl_path = '/foo/bar/baz';
print "This is the Windows path: ", win_path($perl_path), "\n";

sub win_path {
    (my $path = shift) =~ tr!/!\\!;
  return $path;
}

So there you have it. Paths in Perl. By using a / you make it much easier to port your code to another system. For truly portable methods look into the File::Spec module (part of the standard distro) and perlman:perlport. Thanks to wog and Hanamaki for this suggestion. And if you have been converting / to \\ ....