Mini Shell

/* print histogram of integer attribute */
BEGIN {
  int count[];
  int maxd = 0;
  int i, d, v;
  char* attrname = ARGV[0];
}
N{ 
  v = (int)(aget($,attrname));
  count[v]++;
  if (v > maxd) {
    maxd = v;
  }
}
END {
  for (i = 1; i <= maxd; i++) {
    d = count[i];
    if (d > 0) printf ("[%d] %d\n", i, d);
  }
}