i think your regex is fine (though it could be combined into one as blake suggests). when i run the code above, it overwrites the array on each iteration, so it will always contain a single element -- the last in your file. i'd use push:

open (LOG, "$calog") or die "Can't open $calog: $!\n";
while ($line = <LOG>){ 
     if ($line =~ /\'([\w.]+)\' added/) {
      push(@certs, $1);
 } 
}
[download]

--cricket