url http://nginx.org/en/download.html
version_link '.*-([0-9]+[.][0-9]*[02468]([.][0-9]+)*)[.]tar[.][a-z0-9]*$'
do_overwrite() {
ensure_hash
set_var_value version "$CURRENT_VERSION"
set_var_value sha256 "$CURRENT_HASH"
}