2>&1 > output.log

2>&1 | tee output.log

(echo hello | tee xyzzy.txt) >plugh.txt

2>&1 > output.log

2>&1 | tee output.log

> output.log  2>&1

utility 2>&1 >output.log

utility 2>&1 | tee output.log

STDIN - Standard Input - Writes from an input device to the program
STDOUT - Standard Output - Writes program output to screen unless specified otherwise.
STDERR - Standard Error Output - Writes error messages. Also printed to the screen unless specified otherwise.