awk 计算各列的平均值

用awk来计算，用一个关联数组sum来计算列 的数据和，假设文件为file.txt
awk '
{
for (i=2;i<=NF;++i)
{
sum[i]+=$i
if (NR == 1 || min[i] > $i) { min[i] = $i }
if (NR == 1 || max[i] < $i) { max[i] = $i}
}
colum = NF;
row = NR
}
END {
printf ("average: ");
for (i=2; i<= colum; ++i)
{
printf("%f ", sum[i]/row);
}
print ""

printf ("max: ");
for (i=2; i<= colum; ++i)
{
printf("%s ", max[i]);
}
print ""
printf ("min: ");
for (i=2; i<= colum; ++i)
{
printf("%s ", min[i]);
}
print ""
}
' file.txt