[SOLVED] Redirect copy of stdin to file from within bash script itself

Issue

In reference to https://stackoverflow.com/a/11886837/1996022 (also shamelessly stole the title) where the question is how to capture the script's output I would like to know how I can additionally capture the scripts input. Mainly so scripts that also have user input produce complete logs.

I tried things like

exec 3< <(tee -ia foo.log <&3)
exec <&3 <(tee -ia foo.log <&3)

But nothing seems to work. I'm probably just missing something.

Solution

Maybe it'd be easier to use the script command? You could either have your users run the script with script directly, or do something kind of funky like this:

#!/bin/bash

main() {
    read -r -p "Input string: "
    echo "User input: $REPLY"
}

if [ "$1" = "--log" ]; then
    # If the first argument is "--log", shift the arg
    # out and run main
    shift
    main "$@"
else
    # If run without log, re-run this script within a
    # script command so all script I/O is logged
    script -q -c "$0 --log $*" test.log
fi

Unfortunately, you can't pass a function to script -c which is why the double-call is necessary in this method.

If it's acceptable to have two scripts, you could also have a user-facing script that just calls the non-user-facing script with script:

script_for_users.sh
--------------------
#!/bin/sh
script -q -c "/path/to/real_script.sh" <log path>

real_script.sh
---------------
#!/bin/sh
<Normal business logic>

Answered By - John Moon