post_install() {
  grep -q '^/bin/brush$' etc/shells || echo '/bin/brush' >> etc/shells
  grep -q '^/usr/bin/brush$' etc/shells || echo '/usr/bin/brush' >> etc/shells
}

post_upgrade() {
  post_install
}

pre_remove() {
  sed -i -E -e '/^(\/usr)?\/bin\/brush$/d' etc/shells
}
