--fail will make the exit status nonzero on a failed request. Using
--head will avoid downloading the file contents, since we don’t need it for this check. Using
--silent will avoid status or errors from being emitted by the check itself.
if curl --output /dev/null --silent --head --fail "$url"; then echo "URL exists: $url" else echo "URL does not exist: $url" fi
If your server refuses HEAD requests, an alternative is to request only the first byte of the file:
if curl --output /dev/null --silent --fail -r 0-0 "$url"; then