{
  writeShellApplication,
  gnugrep,
  gnused,
  nix-prefetch-svn,
  subversion,
}:
writeShellApplication {
  name = "sword-updater";
  runtimeInputs = [
    gnugrep
    gnused
    nix-prefetch-svn
    subversion
  ];

  text = ''
    url="https://www.crosswire.org/svn/sword/trunk"
    old_rev="$(grep "${./flake.nix}" -e "rev = " | sed -E -e 's/.*"(.*)".*/\1/')"
    echo "OLD_REV=$old_rev"
    new_rev="$(svn info "$url" --show-item revision)"
    echo "NEW_REV=$new_rev"
    if [ "$new_rev" == "$old_rev" ]; then
      exit 0
    else
      echo "DO_UPDATE=1"
    fi
    hash="$(nix-prefetch-svn \
        "$url" \
        "$new_rev" \
    )"
    echo "HASH=$hash"
    sed -i flake.nix \
        -e "s/rev = \"$old_rev\"/rev = \"$new_rev\"/"
  '';
}