$path =~ s/\\/\//g;
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use strict;
use File::Spec;
use File::Spec::Unix;

my $path = "C:\\Dir1\\Dir2";

print "Path before change :$path:\n";

$path =~ s/\\/\//g;

print "Path after change :$path:\n";

#####################################

my $fs_path = File::Spec->catdir('C:','Dir1','Dir2');

print "Path before change :$fs_path:\n";

$fs_path=File::Spec::Unix->catdir($fs_path);

print "Path after change :$fs_path:\n";
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It's not a builtin-part-of-the-language, but File::Spec is builtin-part-of-the-core-distribution (see perlmodlib for the complete list).

While reading the title of OP, I was also thinking of using File::Spec module. In my version, however, usage of that module would have been limited only to get the path separator for the host OS|file system, and '/' would have been used literally per request.

If you want something that doesn't hurt the eyes, try this for size:

$path =~ s(\\)(/);
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What you have is referred to as the Leaning Toothpick Syndrome.