foreach $exch(@exch) { 
    for($i=0; $i<=$#completefile; $i++) { 
        $su_adapter = undef;
        $su_date = undef;
        while($completefile[$i]=~ m/^.+\\(.+)_.+\..+?:(.+?)\s-\s(.+?)\s.+?\/$exch\s\|.+::(.*Up)\(\)/g) { 
            $su_adapter=$1; 
            $su_date=$2; 
        }
        print $su_adapter, $su_date;
    }
}

##</code><code>##

foreach my $exch (@exch) {
    my ($su_adapter, $su_date);
    foreach (reverse @completefile) {
        last if ($su_adapter, $su_date) = /^.+\\(.+)_.+\..+?:(.+?)\s-\s(.+?)\s.+?\/$exch\s\|.+::(.*Up)\(\)/;
    }
    if (defined $su_adapter) {
        print "Last match for $exch: $su_adapter, $su_date\n";
    } else {
        print "No match for $exch\n";
    }
}