
We could have added the last script anywhere in `/env`. But `/env/bin` is
already in the executable search `PATH`, so you don't have to write out
the full path when invoking the script. Another special directory is
`/env/init`. Anything there will be sourced on shell startup.
Let's poke the HTIF a bit every time we start: Open a new file with
`edit /env/init/99-percent` and type into it `putc 0x40`.

