This script will convert an official Vivaldi Linux package into Slackware package format (it should work on any Linux distro, under macOS or even using BusyBox tools)

viv2slk.sh

#!/bin/sh -eu

# This script will convert an official Vivaldi Linux package into Slackware
# package format.
#
# To use, just run this script, followed by the name of the Vivaldi package.
#
# Note: Since this script was created with Slackware 15 and above in mind, it
# uses the new 'douninst.sh' script to clear down any proprietary media libs
# fetched by 'update-ffmpeg' during post install.
#
# If you run 14.2, the UNINSTALL-Slackware-14.2.txt in the doc directory
# (also mentioned below) explains any post cleanup you might wish to perform.

# Take the first command line argument as the name of the Vivaldi package or
# if nothing is provided, look in the current working directory for the most
# recent file named like a Vivaldi package
if [ -n "${1:-}" ]; then
  VIVPKG="$1"
else
  VIVPKG="$(ls -dt vivaldi-s* 2>/dev/null | grep -m1 '\.\(deb\|rpm\)$' 2>/dev/null ||:)"
  if [ -n "${VIVPKG:-}" ]; then
    echo "Found \"$VIVPKG\" as a potential source package."
  else
    echo "No Vivaldi package was found in the current working directory" >&2
    exit 1
  fi
fi

# Check that the package is correctly named
if ! echo "${VIVPKG##*/}" | grep -qxE "vivaldi-(stable|snapshot)[_-](([0-9]+\.){3}[0-9]+)-[0-9]+[_\.](aarch64|amd64|arm64|armhf|armv.hl|x86_64)\.(rpm|deb)"; then
  echo "\"${VIVPKG##*/}\" is oddly named." >&2
  echo "Specify the name of the package you wish to convert as the first argument to this script." >&2
  exit 1
fi

# Check that the package is present and readable on the filesystem
if ! [ -r "$VIVPKG" ]; then
  echo "\"${VIVPKG##*/}\" cannot be accessed." >&2
  exit 1
fi

# Set some basic variables
case "$VIVPKG" in
  *rpm)
    PKGNAME="$(echo "${VIVPKG##*/}" | cut -d- -f1-2)"
    VERSION="$(echo "${VIVPKG##*/}" | cut -d- -f3)"
    ARCH="$(echo ${VIVPKG%.rpm} | cut -d. -f5)"
  ;;
  *deb)
    PKGNAME="$(echo "${VIVPKG##*/}" | cut -d_ -f1)"
    VERSION="$(echo "${VIVPKG##*/}" | cut -d_ -f2 | cut -d- -f1)"
    ARCH="$(echo ${VIVPKG%.deb} | cut -d_ -f3)"
  ;;
esac
case $ARCH in
  aarch64|arm64) ARCH=arm64 ;;
  amd64) ARCH=x86_64 ;;
  arm*) ARCH=arm ;;
esac
BUILD=${BUILD:-1}
TAG=${TAG:-ruario}
PKGTYPE="${PKGTYPE:-tbz}"
OUTPUT="$PWD"
PACKAGE="$OUTPUT/$PKGNAME-$VERSION-$ARCH-$BUILD$TAG.$PKGTYPE"
REPACKDIR="$(mktemp -d -t vivaldi-repackage.XXXXXX)/pkg"

# This function can be used in place of Slackware's makepkg, with the added
# bonuses that it is able to make packages with root owned files when run as
# a regular user and it will work on macOS. It will also work under BusyBox
# (if you are root).
mkpkg() {
  if find * -type l | grep -qm1 .; then
    mkdir -p install
    find * -type l -print0 |\
      xargs -0 -I@ sh -c 'for l in "@";do printf "(*cd*${l%/*}*;*"; echo "rm*-rf*${l##*/}*)"; printf "(*cd*${l%/*}*;*"; echo "ln*-sf*"$(readlink "$l")"*${l##*/}*)"; done' |\
      sed 's/ /\\ /g;s/\*/ /g' > install/symlinks
    find * -type l -delete
    if [ -f "install/doinst.sh" ]; then
      printf '\n' | cat - install/doinst.sh >> install/symlinks
    fi
    mv install/symlinks install/doinst.sh
  fi
  case "$1" in
    *tbz)
      if command -v lbzip2 >/dev/null 2>&1; then
        COMPRESSOR=lbzip2
      else
        COMPRESSOR=bzip2
      fi
      ;;
    *tgz)
      if command -v pigz >/dev/null 2>&1; then
        COMPRESSOR=pigz
      else
        COMPRESSOR=gzip
      fi
      ;;
    *txz)
      if command -v xz >/dev/null 2>&1; then
        COMPRESSOR='xz -T0'
      # We might still be able to make this work on macOS
      elif tar --version | grep -q 'libarchive.*liblzma'; then
        LIBARCHIVEXZ=J
        COMPRESSOR='cat -'
      else
        echo "No XZ compressor found" >&2
        exit 1
      fi
      ;;
    *)
      echo "Unknown compression type" >&2
      exit 1
      ;;
  esac
  if tar --version | grep -q libarchive; then
    (echo ./; find *) | tar --no-recursion -T- --uname root --gname root -c${LIBARCHIVEXZ:-}f- | $COMPRESSOR > "$1"
  else
    # I would like this script to work on any system but BusyBox tar does not
    # allow changing permissions of the fly. However if the script is run as
    # root it should work in a pure BusyBox environment as well.
    if tar --version | grep -q busybox; then
      if [ "$(whoami)" = 'root' ];then
        chown -R root:root .
      else
        echo "To run this under BusyBox, you must be root" >&2
        cd "$OUTPUT"
        rm -r "$REPACKDIR"
        exit 1
      fi
    else
      TAR_OWNERSHIP="--owner root --group root"
    fi
    (echo ./; find *) | tar --no-recursion -T- ${TAR_OWNERSHIP:-} -cf- | $COMPRESSOR > "$1"
  fi
  echo "Slackware package \"${1##*/}\" created."
}

# Make the basic directory structure
mkdir -p "$REPACKDIR/install" "$REPACKDIR/var/lib/pkgtools/douninst.sh" "$REPACKDIR/usr/doc/$PKGNAME-$VERSION"

# Add a this script to doc directory
cat "$0" > "$REPACKDIR/usr/doc/$PKGNAME-$VERSION/${0##*/}"

# Extract the to the repacking directory.
correct_offset () {
  # Some strings implementations output the offset as octal, test for this
  # and convert to decimal if needed (note: '-td' is not always available)
  [ "$(printf 'popular\novel' | strings -o | sed -n '/v/s/ *\([0-9][0-9]*\) .*/\1/p')" -eq 10 ] && XZ_OFFSET="$(printf '%d' "0$XZ_OFFSET")"
}
if [ "${VIVPKG##*.}" = 'rpm' ]; then
  if command -v bsdtar >/dev/null 2>&1; then
    bsdtar Cfx "$REPACKDIR" "$VIVPKG" ./opt ./usr
  else
    XZ_OFFSET="$(strings -o "$VIVPKG" | grep -Fm1 7zXZ | sed 's/ *\([0-9][0-9]*\) .*/\1/')"
    correct_offset
    tail -c+"$XZ_OFFSET" "$VIVPKG" | xz -d | (cd "$REPACKDIR" && cpio --quiet -id ./opt\* ./usr\*)
  fi
else
  if command -v bsdtar >/dev/null 2>&1; then
    bsdtar xOf "$VIVPKG" data.tar.xz | bsdtar Cfx "$REPACKDIR" - ./opt ./usr
  else
    XZ_OFFSET="$(strings -o "$VIVPKG" | grep -Fm2 7zXZ | tail -n1 | sed 's/ *\([0-9][0-9]*\) .*/\1/')"
    correct_offset
    tail -c+"$XZ_OFFSET" "$VIVPKG" | xz -d 2>/dev/null | tar -C "$REPACKDIR" -xf - ./opt ./usr
  fi
  # These only contain Debian specific stuff
  rm -rf "$REPACKDIR/usr/share/doc" "$REPACKDIR/usr/share/menu" "$REPACKDIR/opt/${PKGNAME%-stable}/cron"
fi

# Add a 'vivaldi' symlink for stable
cd "$REPACKDIR"
[ "${PKGNAME%-stable}" = 'vivaldi' ] && ln -s /opt/${PKGNAME%-stable}/${PKGNAME%-stable} usr/bin/${PKGNAME%-stable}

# Setup icons for use with the .desktop file.
for PNG in opt/${PKGNAME%-stable}/product_logo_*.png; do
  PNG_SIZE="$(echo $PNG | grep -o '[0-9]\+')"
  mkdir -p usr/share/icons/hicolor/${PNG_SIZE}x$PNG_SIZE/apps
  ln -s /$PNG usr/share/icons/hicolor/${PNG_SIZE}x$PNG_SIZE/apps/${PKGNAME%-stable}.png
done

# Add various package meta-data
cat <<EOF>install/slack-desc
$PKGNAME: $PKGNAME (web browser)
$PKGNAME:
$PKGNAME: Experience the web in a whole new way with Vivaldi.
$PKGNAME:
$PKGNAME: Vivaldi is a browser that has the features you need, a style that fits
$PKGNAME: and values you can stand by. Your browser matters. Take control with
$PKGNAME: Vivaldi.
$PKGNAME:
$PKGNAME: Home Page: https://vivaldi.com
$PKGNAME:
$PKGNAME:
EOF
cat <<EOF>install/doinst.sh
if [ -x /usr/bin/update-desktop-database ]; then
  /usr/bin/update-desktop-database -q usr/share/applications >/dev/null 2>&1
fi
# Installs a third party libffmpeg.so that supports proprietary media
if [ -x /opt/${PKGNAME%-stable}/update-ffmpeg ]; then
  nohup /opt/${PKGNAME%-stable}/update-ffmpeg >/dev/null 2>&1 &
fi
EOF
cat <<EOF>var/lib/pkgtools/douninst.sh/$PKGNAME-$VERSION-$ARCH-$BUILD$TAG
# Remove any lib fetched by update-ffmpeg, when doinst.sh was first run
if ls /var/opt/${PKGNAME%-stable}/media-codecs-*/libffmpeg.so >/dev/null 2>&1; then
  rm /var/opt/${PKGNAME%-stable}/media-codecs-*/libffmpeg.so
fi
if [ -d /var/opt/${PKGNAME%-stable} ]; then
  # This removes directory trees that are empty or only populated by other
  # empty directories.
  find /var/opt/${PKGNAME%-stable} -depth -type d -empty -exec rmdir {} \;
fi
EOF
chmod +x var/lib/pkgtools/douninst.sh/$PKGNAME-$VERSION-$ARCH-$BUILD$TAG

# Add a note about uninstall on Slackware 14.2
cat <<EOF>"$REPACKDIR/usr/doc/$PKGNAME-$VERSION/UNINSTALL-Slackware-14.2.txt"
Since '${0##*/}' was created with Slackware 15 and above in mind, it uses the
new 'douninst.sh' script to clear down any proprietary media libs fetched by
'update-ffmpeg' during post install.

If you run ≤14.2, make a copy of the douninst.sh *before* uninstall:

  cp /var/lib/pkgtools/douninst.sh/$PKGNAME-$VERSION-$ARCH-$BUILD$TAG .

Then simply run it as root after uninstall.

(If you forget it is not the end of the world, you will just potentially
leave behind a small file [libffmpeg.so] under /var/opt/vivaldi*)
EOF

# Make sure the file permissions are ok
chmod -R u+w,go+r-w,a-s .

# Create the Slackware package
mkpkg "$PACKAGE"

# Cleanup
cd "$OUTPUT"
rm -r "$REPACKDIR"