#!/bin/bash

if [ "$EUID" -ne 0 ]
then
    echo "root privilege is required. re-run this script with 'sudo'." >&2
    exit 1
fi

TEMP_PATH=$(tempfile -d $(pwd))

function clear_cache {
    /sbin/sysctl -w vm.drop_caches=3 > /dev/null 2>&1
}

function test_write {
    clear_cache
    sync
    dd if=/dev/zero of=$TEMP_PATH bs=5M count=256
    sync
}

function test_read {
    clear_cache
    sync
    dd if=$TEMP_PATH of=/dev/null bs=5M count=256
    sync
}

echo -e "measuring write speed...\c"
WRITE_SPEED=$(test_write 2>&1 | grep copied | rev | cut -d ' ' -f 1-2 | rev)
echo -e "\rmeasuring write speed... $WRITE_SPEED"
echo -e "measuring read speed...\c"
READ_SPEED=$(test_read 2>&1 | grep copied | rev | cut -d ' ' -f 1-2 | rev)
echo -e "\rmeasuring read speed... $READ_SPEED"
rm -rf $TEMP_PATH