Imagine you have a piece of code that tries to send a request to a remote server. Now the server is temporarily not available and raises an exception. In order to re-send the request you could use the following snippet:

def remote_request
  begin
    response = RestClient.get my_request_url
  rescue RestClient::ResourceNotFound => error
    @retries ||= 0
    if @retries < @max_retries
      @retries += 1
      retry
    else
      raise error
    end
  end
  response
end

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This snippet tries to re-send the request when ResourceNotFound was thrown until @max_retries (termination condition) was reached. With the retry statement you can re-execute the begin block that has been rescued from. Be aware that you could run into an infinite loop without a termination condition.