You probably want something like this (UNTESTED):

#!/usr/bin/perl
use warnings;
use strict;

unless ( @ARGV == 2 ) {
    die "Need both new candidate list and candidate list archive!\n";
}

my ( $can_list, $can_archive ) = @ARGV;


# Open candidate list
open LIST, '<', $can_list or die "Cannot open new candidate list file!
+ $!";

chomp( my @new_candidates = <LIST> );

# Open results log
open LOG, '>', '/data/My Documents/candidates_results.log' or die "Cou
+ld not open candidate search log: $!";


open LIST, '<', $can_archive or die "Cannot open '$can_archive' $!";

while ( my $line = <LIST> ) {
    foreach my $result ( @new_candidates ) {
        print LOG $line if $line =~ /$result/i;
    }
}

close LOG; 
close LIST;
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