Question

I want to process some log file whose format is like:

<itemA>    <num>
<itemB>    <num>
<itemC>    <num>

I want to get a summary that contains the following information

for each item I want to know the range of the <num> field and the average of <num>

Answer 1

I agree with Seth, and prefer his answer. Here is a manual solution in Awk, for learning purposes:

#!/usr/bin/awk -f
#invoke with: < infile stats.awk
{
  i = $1; v = $2;
  count[i]++; 
  sum[i] += v; 
  if (v > max[i] || count[i] == 1) { max[i] = v }; 
  if (v < min[i] || count[i] == 1) { min[i] = v };
} 

END {
  for (i in count) {
    print i " range: " min[i] ".." max[i] " avg: " sum[i] / count[i] 
  }; 
}