count-nginx-access-log-bytes-sent.sh

#!/usr/bin/env sh

filename="${1:--}"

if [ "$filename" = "-" ]; then
  filename="/dev/stdin"
fi

grep_options=( -Po )
if [[ "$OSTYPE" == "darwin"* ]]; then
  grep_options=( -Eo )
fi

first_line=""
last_line=""

count=0
sum=0

while read -r line; do
  SIZE=$(echo "$line" | grep "${grep_options[@]}" "HTTP\/1.1\" \d+ \d+" | grep "${grep_options[@]}" "\d+$")
  if [ $? -ne 0 ]; then
    continue
  fi
  if [ -z "$first_line" ] ; then
    first_line="$line"
  fi
  last_line="$line"
  count=$(( count + 1 ))
  sum=$(( sum + SIZE ))
done < "$filename"

printf "First row: %s\n" "$first_line"
printf "Last row: %s\n" "$last_line"
printf "count=%s\n" "$count"
printf "sum=%s\n" "$sum"
if [ $count -eq 0 ]; then
  printf "AVG=0\n"
else
  printf "AVG=%s\n" $(( sum/count ))
fi