How to redirect output to a file and stdout

Question

In bash, calling foo would display any output from that command on the stdout.

Calling foo > output would redirect any output from that

Answer 1

You can do that for your entire script by using something like that at the beginning of your script :

#!/usr/bin/env bash

test x$1 = x$'\x00' && shift || { set -o pipefail ; ( exec 2>&1 ; $0 $'\x00' "$@" ) | tee mylogfile ; exit $? ; }

# do whaetever you want

This redirect both stderr and stdout outputs to the file called mylogfile and let everything goes to stdout at the same time.

It is used some stupid tricks :

• use exec without command to setup redirections,
• use tee to duplicates outputs,
• restart the script with the wanted redirections,
• use a special first parameter (a simple NUL character specified by the $'string' special bash notation) to specify that the script is restarted (no equivalent parameter may be used by your original work),
• try to preserve the original exit status when restarting the script using the pipefail option.

Ugly but useful for me in certain situations.