A command such as
wget -qO- bench.sh | bash
means "get a file from bench.sh and run it with
This is effectively the same as
wget -q -Otestfile bench.sh
but without needed the temporary file.
So what you are doing is downloading and running untrusted code. Today you can download the file and check it for "nasty" commands, but will it still be clean tomorrow? Or the next day?
Is this a security concern? Potentially.
You need to decide on how much you trust the people running bench.sh and how likely it is that someone will try and break into the server and make unauthorised changes. Also note the connection is via
http so is potentially open to a "man in the middle" attack, changing the data as it is sent to your computer.
I, personally, don't run scripts that way; but I know many people who do.