Shell Programming and Scripting

#!/bin/bash

# Create a fifo
mkfifo /tmp/$$

# Create a background process to read it
tee out.log < /tmp/$$ &
# Redirect stdout into it
exec 1>/tmp/$$
# Uncomment this line to capture stderr as well.
# exec 1>&2

# Delete the fifo now, before we forget
rm /tmp/$$

for ((N=0; N<100; N++))
do
        echo "$N"
done

# close stdout
exec 1>&-
# close stderr too if you redirected it
# exec 2>&-
# wait for tee to quit
wait