That returns the file. What about the second requirement to capture the directory?

use Cwd qw( abs_path );
my $full = abs_path($file_path);
my ($dir, $file) = $full =~ /^(.*)\\(.*)/;  # Wrong for C:\File
my ($dir, $file) = $full =~ /^(.*\\)(.*)/;  # Ugly for C:\Dir\File
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A regular expression is not the way to go here. As seen below, there are better (reliable, tested, portable) options in Core Perl.