Shell Programming and Scripting

exec > imp.log 2>&1 | tee exec 1>&1

#!/usr/bin/ksh
#
#  Within a shell script set up simultaneous output
#  to both terminal and a file using a FIFO
#

# delete output file
OUTPUT=log
[[ -e $OUTPUT ]] && rm $OUTPUT

# set up redirects
exec 3>&1 4>&2
FIFO=fifo.$$
[[ -e $FIFO ]] || mkfifo $FIFO
tee $OUTPUT < $FIFO >&3 &
PID=$!
exec > $FIFO 2>&1

# rest of your shell script here i.e.
echo "STDOUT `date`"
echo "STDERR `date`" >&2
# to here

# exit tee and clean up
exec 1>&3 2>&4 3>&- 4>&-
wait $PID
rm $FIFO

exit 0

{
  echo "STDOUT: xxxxxxxxxxxxxxxxx"
  echo "STDERR: xxxxxxxxxxxxxxxxx" >&2
} 2>&1 | tee imp.log