How to add timestamp to STDERR redirection

Question

In bash/ksh can we add timestamp to STDERR redirection?

E.g. myscript.sh 2> error.log

I want to get a timestamp written on the log too.

Answer 1

Rather than writing a script to pipe to, I prefer to write the logger as a function inside the script, and then send the entirety of the process into it with brackets, like so:

 # Vars    
 logfile=/path/to/scriptoutput.log

 # Defined functions
 teelogger(){
   log=$1
   while read line ; do
     print "$(date +"%x %T") :: $line" | tee -a $log
   done
 }


# Start process
{

echo 'well'
sleep 3
echo 'hi'
sleep 3
echo 'there'
sleep 3
echo 'sailor'

}  |  teelogger $logfile