# ok
my $path = "dir/file.txt";

# not ok 
my $path = "dir\file.txt";

# ok
my $path = "dir\\file.txt";

# also ok - in single quoted strings only sequences \' and \\ are special
my $path = 'dir\file.txt';


##</code><code>##


use File::Spec;

my $path = File::Spec->catfile(qw(dir file.txt));