[Help-bash] Redirecting all output of a script to a log file

[Bernard Fay]

Hello,

I try to have all output of a script send to a log file as well as to the
screen. I do not want to use "scriptname | tee logfile".

Taking a look at the man page of exec, I thought I could do something like
the following sample script:


#!/bin/bash

exec 4<&1       # Make file descriptor 4 a copy of file descriptor 1
exec 5<&2       # Make file descriptor 5 a copy of file descriptor 2
exec 4>${0}.log  5>&4

echo running the script $0
ls -l
echo bye



The logfile ${0}.log is created but empty.

Do I miss something or I am on the wrong track?  Is it feasible the way I
think about it?

Thanks,