Get the app response TTFB ( Time To First Byte ) with curl

wait-ttfb

#!/usr/bin/env bash

set -eu
export LC_ALL=C.UTF-8

CURL_FORMAT="%{time_starttransfer} - %{time_pretransfer}"

declare -a TIMES
for i in {1..15}; do
	OUT_CURL=$(curl -w "$CURL_FORMAT" -k --compressed -s -o /dev/null "$@")
	echo -n "."

	TIMES[i]=$(echo "$OUT_CURL" | bc)
done
echo

IFS=$'\n' SORTED_TIMES=($(sort <<<"${TIMES[*]}")); unset IFS

echo "fastest: ${SORTED_TIMES[0]}     slowest: ${SORTED_TIMES[@]: -1: 1}"
printf "p50: %f\n" "${SORTED_TIMES[@]: -7: 1}"

echo