Write to terminal after redirecting stdout to a file without using stderr?

Question

I have two shell scripts, one that serves as the main \"program\" and another that serves as a \"library.\"

In several places in the \"program,\" I\'ll do something

Answer 1

Open /dev/tty on another FD.

exec 0< /dev/null
exec 1> /dev/null
exec 2> /dev/null
exec 3> /dev/tty
echo 'Hello, World!' >&3 

Answer 2

You can write directly to /dev/tty each time you want to write to the terminal:

echo "hello world" > /dev/tty

For a small example:

$ cat writer.sh 
#!/bin/sh

echo "standard output"
echo "standard error" >&2

echo "direct to terminal" > /dev/tty
$ ./writer.sh > /tmp/out 2> /tmp/err
direct to terminal
$ cat /tmp/out
standard output
$ cat /tmp/err
standard error
$