Test time to first byte for specific URL

ttfb.sh

#!/usr/bin/env sh

# bash ttfb.sh url [num_of_tests]
# bash ttfb.sh https://example.org 11

if [[ -z $@ ]]
then
  echo "Pass url and number of test runs to execute. By default 10 tests are executed."
  echo "bash ttfb.sh url [num_of_tests]"
  echo "E.g: $ bash ttfb.sh https://example.org 10"
  exit 2
fi

if [[ -z $1 ]]
then
  echo "Need an URL to proceed!"
  exit 2
fi

url=$1
tries=10
if [[ ! -z $2 ]]
then
  tries=$2
fi

echo "Testing TTFB $tries times for $url"

# Execute the run
for (( i=0; i<$tries; i++));
do
  res[i]=$(curl -so /dev/null -w "%{time_total}\n" -H "Pragma: no-cache" $url);
done;

# Sort the results numerically and print them.
IFS=$'\n' sorted=($(sort <<<"${res[*]}"))
echo -e "\nSorted Results:\n${sorted[*]}"
unset IFS

min=${sorted[0]}
max=${sorted[$tries-1]}

if  [[ $tries%2 -eq 1 ]]
then
  median=${sorted[$tries/2]}
else
# sorted has zero based index so it ranges from 0 to $tries-1
  P1=${sorted[($tries/2)-1]}
  P2=${sorted[$tries/2]}
  median=$(echo "$P1 $P2" | awk '{print ($1 + $2)/2}')
fi

printf "\nMin: %f\tMax: %f\tMedian: %f\n" $min $max $median;