min & max functions for awk. I was a bit surprised these weren't already in the numeric functions section of the man page already.

min_max.awk

#!/usr/bin/awk -f

function limit_seeker(a, b, direction) {
  _record=b;

  if (isarray(a)) {
    for (k in a) {
      _record=limit_seeker(a[k], _record, direction);
    }
  } else {
    if ("-" == direction) {
      _new_record=_record > a;
    } else {
      _new_record=a > _record;
    }
    if (_new_record) {
      _record=a;
    }
  }

  return _record;
}

function min(a, b) {
  return limit_seeker(a, b, "-");
}

function max(a, b) {
  return limit_seeker(a, b, "+");
}