Content-Range "bytes ${range}/${file_size}" \
Content-Length "$((${range#*-} - ${range%-*} + 1))"
printf '\r\n'
[ "$REQUEST_METHOD" != HEAD ] \
&& tail -c+$((${range%-*} + 1)) "$file" \
Content-Range "bytes ${range}/${file_size}" \
Content-Length "$((${range#*-} - ${range%-*} + 1))"
printf '\r\n'
[ "$REQUEST_METHOD" != HEAD ] \
&& tail -c+$((${range%-*} + 1)) "$file" \