while ( my $proc = <PROCS> ) {
      # if the grep filters out everything, this is a
      # zero-trip loop.
  }

##</code><code>##

  my $found_one = 0;
  while ( my $proc = <PROCS> ) {
      ...
      $found_one = 1;
  }
  if ( $found_one ) {
      print "looks okay here\n";
  } else {
      print "couldn't find $process\n";
  }