\x89\x50\x4E\x47\x0D\x0A\x1A\x0A
 PNG

\x89\x50\x4E\x47\x0D\x0A\x1A\x0A
/* List known node attributes */
BEG_G {
  char* attr;
  for (attr = fstAttr($,"N"); attr != ""; attr = nxtAttr($,"N",attr)) {
    print (attr);
  }
}