redirect.sh

#!/bin/bash

# redirect STDOUT to a file (note the single > -- this will truncate /tmp/outfile)
exec 1> /tmp/outfile

echo Now all STDOUT from each subsiquent command will  
echo be redirected to /tmp/outfile  
echo but not STDERR >&2

# redirect STDERR to STDOUT and append (note the double >>) both to /tmp/outfile
exec 1>> /tmp/outfile 2>&1

echo now we get STDERR too >&2

# We can also turn off all output
echo 1>&-  
echo 2>&-

echo Now you can\'t hear me!