Use CURL to get file size of a given url

file-size.sh

#!/bin/sh

bytesToHuman() {
    b=${1:-0}; d=''; s=0; S=(Bytes {K,M,G,T,E,P,Y,Z}iB)
    while ((b > 1024)); do
        d="$(printf ".%02d" $((b % 1024 * 100 / 1024)))"
        b=$((b / 1024))
        let s++
    done
    echo "$b$d ${S[$s]}"
}

URL=$1

if [ -z "$URL" ]; then
    printf "\nUsage:\n\t file-size URL\n\n"
    exit 0;
fi

NO_GZIP=$(curl "$URL" --silent --write-out '%{size_download}\n' --output /dev/null)
GZIP=$(curl "$URL" --silent -H 'Accept-Encoding: gzip,deflate' --write-out '%{size_download}\n' --output /dev/null)

echo "regular: $(bytesToHuman $NO_GZIP)"
echo "gzipped: $(bytesToHuman $GZIP)"