usr.sbin/traceroute/median.awk

   1 #!/bin/awk -f
   2 #       $NetBSD: median.awk,v 1.5 1997/10/04 16:31:32 christos Exp $
   3 /^ *[0-9]/      {
   4         # print out the median time to each hop along a route.
   5         tottime = 0; n = 0;
   6         for (f = 5; f <= NF; ++f) {
   7                 if ($f == "ms") {
   8                         ++n
   9                         time[n] = $(f - 1)
  10                 }
  11         }
  12         if (n > 0) {
  13                 # insertion sort the times to find the median
  14                 for (i = 2; i <= n; ++i) {
  15                         v = time[i]; j = i - 1;
  16                         while (time[j] > v) {
  17                                 time[j+1] = time[j];
  18                                 j = j - 1;
  19                                 if (j < 0)
  20                                         break;
  21                         }
  22                         time[j+1] = v;
  23                 }
  24                 if (n > 1 && (n % 2) == 0)
  25                         median = (time[n/2] + time[(n/2) + 1]) / 2
  26                 else
  27                         median = time[(n+1)/2]
  28
  29                 print $1, median
  30         }
  31 }