First checkin of evolving new linux installer code

installers/linux/linux_installer.sh

@@ -0,0 +1,89 @@
+#! /bin/sh
+
+get_distro () {
+
+  
+  # try various methods, in order of preference, to detect distro
+  # store result in variable '$distro'
+  #
+  distro=$(lsb_release -i -s 2>/dev/null)
+  #
+  if test -z "${distro}" -a -e /etc/os-release
+  then
+    distro=$(awk -F= '$1 == "ID" {print $2}' /etc/os-release)
+  fi
+  #
+  if test -z "${distro}" -a -e /etc/lib/os-release
+  then
+    distro=$(awk -F= '$1 == "ID" {print $2}' /etc/lib/os-release)
+  fi
+  #
+  if test -z "${distro}" -a -e /etc/lsb-release
+  then
+    distro=$(awk -F= '$1 == "DISTRIB_ID" {print $2}' /etc/lib/lsb-release)
+  fi
+  #
+  if test -z "${distro}" -a -e /etc/debian_version
+  then
+    distro="debian"
+  fi
+  #
+  ls /etc/*-release >/dev/null
+  if test $? -eq 0 -a -z "${distro}"
+  then
+    distro=$(cat /etc/*-release | awk -F= '$1 == "ID" {print $2}' | tail -n 1)
+  fi
+  #
+  if test -z "${distro}"
+  then
+    distro="unknown"
+  fi
+
+  # convert to lowercase
+  distro=$(printf '%s\n' "${distro}" | LC_ALL=C tr '[:upper:]' '[:lower:]')
+
+  echo ${distro}
+
+}
+
+is_pkg_installed_cmd () {
+  distro="$1"
+  if test -z ${distro};
+  then
+    distro="$(get_distro)"
+  fi
+  case "${distro}" in
+
+    alpine)
+      cmd="apk info"
+      ;;
+
+    arch | endeavouros | manjaro)
+      cmd="pacman -Q"
+      ;;
+    debian | mint | mxlinux | popos | raspian | ubuntu | zorinos)
+      cmd="dpkg -l"
+      ;;
+
+    centos | fedora)
+      cmd="rpm -qa"
+      ;;
+
+    opensuse)
+      cmd="zypper search -is"
+      ;;
+
+    *)
+      echo "Warning: do not know which package manager to use for distro: ${distro}"
+      ;;
+
+  esac
+
+  echo "${cmd}"
+}
+
+distro=$(get_distro)
+echo "Distro is ${distro}"
+is_installed=$(is_pkg_installed_cmd "${distro}")
+echo "is_installed cmd is: ${is_installed}"
+