What i'm trying to do is pass argument into the second program in such a way that it takes cmdline-args and is opened with sudo but doesn't have anything to with stdin that i pass to sudo.
Below is an example to understand what i'm trying to do.
echo "mypass" | sudo -S nvim "filename"
Here sudo must take stdin and nvim must take a file-name from cmdline-arg. But nvim opens an unnamed file and puts stdin into that file and doesn't even care about the args i pass to it.
My end goal is not to only open file without entering password but to understand how can i pass arguments the way i want to
Is it even possible?
Simply pass the filename as first argument of your script:
echo "<your password>" | sudo -S nvim "$1"
and call the script with:
./script.sh myfile.txt
Note that the -S option of sudo behaves differently depending if the credentials are already cached or not. Better also use the -k option to invalidate the credentials:
echo "<your password>" | sudo -k -S nvim "$1"