Install script for the Swift Community Apt Repository - https://swiftlang.xyz

swift-apt-repo-install.sh

#! /bin/bash
#
# Install script for the Swift Community Apt Repository - swiftlang.xyz
#

# check distribution version and infer distro with switch/case
## as all distribution versions have different names we can use this information to infer the distribution name.
check_ver () {
  for var in "${SUPPORTED_VER[@]}"
  do
    if grep -q $var tmp_sources.txt;
    then
      vers=$var
      case $vers in
            bookworm|bullseye|buster) dist="debian";;
            lunar|kinetic|jammy|focal|bionic) dist="ubuntu";;
      esac
      break
    fi
  done
}

## raspbian is an edge case
## check for raspbian
check_raspbian () {
  if grep -q "raspbian" tmp_sources.txt;
  then
    dist="raspbian"
  fi
}

check_arch () {
    arch=$(dpkg --print-architecture)
}

## deepin is an edge case
## check for deepin
check_deepin () {
  if grep -q "deepin" tmp_sources.txt;
  then
    dist="debian"
    vers="buster"
  fi
}


## check if dist/version is supported
check_supported () {
    if [ $dist == "unsupported" ] || [ $vers == "unsupported" ]
    then
    echo sorry your system is unsupported.
    echo
    exit 0
    fi
}

## user_input allows the selection of the available repository sections

user_input_all () {
  # User Input
  echo
  echo "--------------- Choose Swift Release Version ---------------"
  echo
  echo " If you always want to have the latest release/stable version of Swift available choose [1],"
  echo " or you can choose the Swift version most suitable for your project."
  echo " The latest release/stable version of Swift in this repository is currently 5.8.1 "
  echo
  echo "---------------------------------------------------------"
  echo
  echo "  1) latest/main - This will update to the latest release/stable version of Swift available"
  echo "  2) Swift version 5.4.* - this will update to the latest point/patch release of Swift 5.4"
  echo "  3) Swift version 5.5.* - this will update to the latest point/patch release of Swift 5.5"
  echo "  4) Swift version 5.6.* - this will update to the latest point/patch release of Swift 5.6"
  echo "  5) Swift version 5.7.* - this will update to the latest point/patch release of Swift 5.7"
  echo
  echo "---------------------------------------------------------"
  echo
  read -r -p "Enter number [1/2/3/4/5] : " n < /dev/tty
  echo
  case $n in
    1) main=" main"; echo "Installing the Swift main/latest repository"; echo;;
    2) v5_4=" v5_4"; main=""; echo "Installing the Swift version 5.4.* repository"; echo;;
    3) v5_5=" v5_5"; main=""; echo "Installing the Swift version 5.5.* repository"; echo;;
    4) v5_6=" v5_6"; main=""; echo "Installing the Swift version 5.6.* repository"; echo;;
    5) v5_7=" v5_7"; main=""; echo "Installing the Swift version 5.7.* repository"; echo;;
    *) echo "Invalid option"; echo; exit 1;;
  esac
}

user_input_armhf () {
  # User Input
  echo
  echo "--------------- Choose Swift Release Version ---------------"
  echo
  echo " If you always want to have the latest release/stable version of Swift available choose [1],"
  echo " or you can choose the Swift version most suitable for your project."
  echo " The latest release/stable version of Swift in this repository is currently 5.7 "
  echo
  echo "---------------------------------------------------------"
  echo
  echo "  1) latest/main - This will update to the latest release/stable version of Swift available"
  echo "  2) Swift version 5.1.* - this will update to the latest point/patch release of Swift 5.1.5"
  echo
  echo "---------------------------------------------------------"
  echo
  read -r -p "Enter number [1/2] : " n < /dev/tty
  echo
  case $n in
    1) main=" main"; echo "Installing the Swift main/latest repository"; echo;;
    2) v5_1=" v5_1"; main=""; echo "Installing the Swift version 5.1.* repository"; echo;;
    *) echo "Invalid option"; echo; exit 1;;
  esac
}

## check gpg is installed
gpg_check () {
  echo "Checking for gpg..."
  if command -v gpg > /dev/null; then
    echo "Detected gpg..."
  else
    echo -n "Installing gnupg for GPG verification... "
    apt-get install -y gnupg &> /dev/null
    echo "done."
    if [ "$?" -ne "0" ]; then
      echo "Unable to install GPG! Your base system has a problem; please check your default OS's package repositories because GPG should work."
      echo "Repository installation aborted."
      exit 1
    fi
  fi
}

install_debian_keyring () {
  if [ "${dist}" = "debian" ]; then
    echo "Installing debian-archive-keyring which is needed for installing "
    echo "apt-transport-https on many Debian systems."
    apt-get install -y debian-archive-keyring &> /dev/null
  fi
}

file_check () {
  if [ -f "$apt_source_path" ]
  then
    rm $apt_source_path
    # remove old format list file
    rm -f /etc/apt/sources.list.d/swiftlang.list
  fi
}

main() {
    # default repo values
    v5_1=""
    v5_4=""
    v5_5=""
    v5_6=""
    v5_7=""
    main=" main"
    # default values
    gpg_key="swiftlang_repo.gpg.key"
    gpg_key_url="https://archive.swiftlang.xyz/swiftlang_repo.gpg.key"
    apt_source_path="/etc/apt/sources.list.d/swiftlang-release.list"
    # SUPPORTED_DIST=('ubuntu' 'debian' 'raspbian')
    SUPPORTED_VER=('lunar' 'kinetic' 'jammy' 'focal' 'bionic' 'bookworm' 'bullseye' 'buster')
    # default to unsupported
    dist="unsupported"
    vers="unsupported"
    # ----
    # run apt update
    echo -n "running update... "
    apt-get update > tmp_sources.txt
    echo "done."
    # scan tmp_sources.txt
    echo -n "scanning sources... "
    #check_dist
    check_arch
    check_ver
    check_deepin
    check_raspbian
    echo "done."
    # clean tmp file
    rm tmp_sources.txt
    # check if system is supported - if not - exit
    check_supported
    # if ok continue with install
    # ----
    echo system detected is compatible with $dist/$vers
    echo
    # check prerequisists
    gpg_check
    install_debian_keyring
    echo -n "Installing apt-transport-https... "
    apt-get install -y apt-transport-https &> /dev/null
    echo "done."
    # import the gpg key
    echo -n "Importing swiftlang gpg key... "
    sudo rm /usr/share/keyrings/${gpg_key} &> /dev/null
    curl -fsSL "${gpg_key_url}" | sudo gpg --dearmor -o /usr/share/keyrings/${gpg_key}
    echo "done."
    # user input
    if [ "${arch}" == "armhf" ];
    then
        case $vers in
            bionic|focal|jammy|buster|bullseye) user_input_armhf;;
            *) user_input_armhf;;
        esac
    elif [ "${dist}" != "raspbian" ];
    then
        case $vers in
            bionic|focal|jammy|kinetic|lunar|buster|bullseye|bookworm) user_input_all;;
            *) user_input_all;;
        esac
    fi

    # add source list file
    echo -n "Installing $apt_source_path... "
    file_check
    echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/$gpg_key] https://archive.swiftlang.xyz/$dist/ $vers$v5_1$v5_4$v5_5$v5_6$v5_7$main" | sudo tee $apt_source_path > /dev/null
    echo "done."
    #
    echo -n "Running apt-get update... "
  # update apt on this system
  apt-get update &> /dev/null
  echo "done."

  echo
  echo "The repository is setup!"
  echo "You can now install swift using 'sudo apt install swiftlang' "
  echo
  echo
  echo "+---------------------------------  ❤️   ---------------------------------+"
  echo "│ Please help support this repository at 'https://ko-fi.com/futurejones' │"
  echo "+------------------------------------------------------------------------+"
  echo
}

main

I had to add a swift.conf to /etc/ld.so.conf.d/
That contained

/usr/lib/swift/linux

Update to add swift 5.8 and Ubuntu 23.04 / lunar

Update to add Debian 12 bookworm

Seems like archive.swiftlang.xyz is down, for good now it seems :-(
https://forums.swift.org/t/new-swift-package-repository-for-ubuntu-debian-linux-distributions/50412/137

@Macariel info and updates about the repo can be found on the swift forums
https://forums.swift.org/t/new-swift-package-repository-for-ubuntu-debian-linux-distributions/50412/137

Found it as well in the meanwhile. Sorry for creating any inconveniences 🙈