candidates.pl

use strict;
use warnings;
use File::Spec;

my @candidates = (
	File::Spec->catfile('/', 'usr', 'bin', 'zip'),
	File::Spec->catfile('/', 'usr', 'local', 'bin', 'zip'),
	File::Spec->catfile('C:', 'bin', 'zip'),  # for Windows
);

my ($found) = grep -f, @candidates;

print "Found it at '$found'!\n";