post_install() {
        echo "Adding oksh to /etc/shells..."
        grep -qe '^/usr/bin/oksh$' etc/shells || echo '/usr/bin/oksh' >> etc/shells
}

post_upgrade() {
        post_install
}

pre_remove() {
        echo "Removing oksh from /etc/shells..."
        sed -i '\|^/usr/bin/oksh$|d' etc/shells
}
