$string = 'complex';

open(REF, "<file1");
chomp;

my %pd_file = map { /^(\S+)\s+(\S+).*/;  } <REF>;

close(REF);

open (ET, "<file2");
while (<ET>) {
   chomp;
/^(\S+\s+\S+)\s+.*($string\.\d+).*$/;
   print OUT  ($1,  $pd_file{$2}) if (exists($pd_file{$2}));