8eaf595fe6
Here the trick is to restore those file descriptors (0, 1, 2) that have been redirected (`dup2`) by the parent process. First we need to determine which one has been redirected, for example by looking at `ls -l /proc/$$/fd/`. Then we can use `0<&x`, `1>&x` or `2>&x` to restore 0, 1 or 2 respectively, where `x` is any file descriptor number that points to the TTY. It may happen that no file descriptor is unchanged, in that case we can use `tty` to perform the redirection: sh <$(tty) >$(tty) 2>$(tty)
