#!/bin/bash

LOGFILE="/my/log/file.log"
exec > >(tee "$LOGFILE") 2>&1
# This will tee both stout and sterr to terminal and logfile for the entirity of the script.
# Useful if you cannot / don't want to wrap the script execution in a redirect at call time.
# Stops you having to put '...| tee $LOGFILE 2>&1' on every other line of your script.
#