How to redirect output to a file and stdout?

Question

In bash, calling `foo` would display any output from that command on the stdout. Calling `foo > output` would redirect any output from that command to the file specified (in this case 'output'). Is there a way to redirect output to a file *and* have it display on stdout?

Answer 1

There is a command for this exact scenario called tee. Running the following command would echo to stdout as well as to a file called hello.log. For more look at the man pages!

echo "foo" | tee hello.log