Get URL Load Speed Using CURL

curl_timer.sh

#!/usr/bin/env bash
case $1 in
    http*)
        URL="$1"
        ;;
    *)
        echo "Please provide URL as positional parameter. i.e.: ./script <url>"
        exit 1
        ;;
esac

set -euo pipefail
TIMING='time_spent:\t%{time_total}\n'
for ((i=0;i<500;i++)); do
    echo iteration $(($i+1))
    curl \
        -k \
        -m 3 \
        -s \
        -o /dev/null \
        -D - \
        -w ${TIMING} \
        ${URL}
done 2>&1 | grep -iP 'time_spent:|age:|iteration'