# exec
#
# Shell builtin command
# It can start a new process to replace the shell, without a new process creation.
# It can make redirections take effect in the current shell

# Redirect the output of an entire shell script within the script itself
# Only stdout:
exec > foo.log

# Redirect the output of an entire shell script within the script itself
# Stdout and stderr:
exec > foo.log 2>&1

# Copy output to a log file
exec >  >(tee -ia foo.log)
exec 2> >(tee -ia foo.log >&2)