# spawn a minimally set up mksh - useful if you want to umount /usr/.
emulate -L zsh

local shell="/bin/mksh"
local env_file="/etc/minimal-shellrc"

if [[ ! -x ${shell} ]]; then
    printf '`%s'\'' not available, giving up.\n' ${shell} >&2
    return 1
elif [[ ! -f ${env_file} ]]; then
    printf 'minimal-shell: Configuration missing: `%s'\''\n' ${shell} >&2
    return 2
fi

exec env -i ENV="$env_file" HOME="$HOME" TERM="$TERM" ${shell}