Piping the output of `curl` or `wget -O-` to a shell is a very bad idea for multiple reasons; security concerns aside, doing so provides no opportunity for the script's download to finish before execution starts, so if the download is interrupted for some reason (perhaps because of an intermittent network failure), the incompletely-downloaded script will still run with potentially disastrous results.  See [here](http://www.seancassidy.me/dont-pipe-to-your-shell.html) for a more in-depth description.