Nomen est omen (AKA "the name is a sign"). Please see also File::Basename.

Update:

#!/usr/bin/env perl                                                   
+                          

use strict;
use warnings;
use File::Basename;

my $fullpath = q(/Users/karl/monks/basename.pl);
my $basename = basename($fullpath);
my $dirname  = dirname($fullpath);

print qq(\$fullpath: $fullpath\n);
print qq(\$basename: $basename\n);
print qq(\$dirname: $dirname\n);

__END__

karls-mac-mini:monks karl$ ./basename.pl                              
+                          
$fullpath: /Users/karl/monks/basename.pl
$basename: basename.pl
$dirname: /Users/karl/monks
[download]

Regards, Karl