Unix: confusing use of the Tee -command

Question

Manual states that the tee is a \"pipe fitting\"-tool. The cases [1] confuse me:

1. case

echo \"foo bar\" | sudo tee -a /path/to/some/fi         


        

Answer 1

tee simply mirrors the output into a file that can be specified as the argument to tee.

In the case you show tee is called as the super user (via sudo) and it's sole purpose is to write a file as the super user instead if the user that does the echo.