Have you considered using a module designed for parsing paths?

use File::Basename;
use Data::Dumper;

my @oldlist = qw X /etc/passwd /etc/group /egg/drop /etc/shadow X;
my @newlist = map {basename $_} @oldlist;

print Dumper \@newlist;
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outputs:

$VAR1 = [
          'passwd',
          'group',
          'drop',
          'shadow'
        ];
[download]