------------------------------------------------------------------------ tee ------------------------------------------------------------------------ tee allows you to write to a file (or files) and still pass the input stream to the terminal. The usage is "| tee" always. $ ls | tee file results in the list of files in current directory written to "file" and also displayed on terminal. Thus, $ ls | tee file | wc -l will result in "file" and also list the number of files being displayed. You can be fancier $ echo "number of files:" $(ls | tee file | wc -l) $ ls | tee a b c will result in the input stream written to three files, "a", "b" and "c" $ ls | tee -a b will append the input stream to file "b"