feat: get.sh for simpler installation

scripts/get.sh

@@ -0,0 +1,96 @@
+#!/bin/bash
+
+## Derived from https://github.com/goreleaser/get/blob/03c4bfde763b30bfe270892ab3ff74949d8e9351/get
+
+set -e
+
+die () {
+    echo >&2 "$@"
+    exit 1
+}
+BINARY_NAME="ghc"
+TAR_FILE="/tmp/${BINARY_NAME}.tar.gz"
+RELEASES_URL="https://github.com/bartoszmajsak/github-changelog-generator/releases"
+
+show_help() {
+  echo "get - downloads ${BINARY_NAME} binary matching your operating system"
+  echo " "
+  echo "./get.sh [options]"
+  echo " "
+  echo "Options:"
+  echo "-h, --help          shows brief help"
+  echo "-v, --version       defines version specific version of the binary to download (defaults to latest)"
+  echo "-d, --dir           target directory to which the binary is downloaded (defaults to random tmp dir in /tmp suffixed with ${BINARY_NAME}-version)"
+}
+
+last_version() {
+  curl -sL -o /dev/null -w %{url_effective} "$RELEASES_URL/latest" |
+    rev |
+    cut -f1 -d'/'|
+    rev
+}
+
+download() {
+  version=$1
+  if [[ ${version} == "" ]]; then
+    echo >&2 "Undefined version (pass using -v|--version). Please use semantic version. Read more about it here: https://semver.org/ \n\n"
+    show_help
+    exit 1
+  fi
+
+  url="$RELEASES_URL/download/$version/${BINARY_NAME}_${version:1}_$(uname -s)_$(uname -m).tar.gz"
+
+  rm -f "$TAR_FILE"
+  curl -fsLo "$TAR_FILE" "$url" || die "Unable to download $url"
+}
+
+while test $# -gt 0; do
+  case "$1" in
+    -h|--help)
+            show_help
+            exit 0
+            ;;
+    -v)
+            shift
+            if test $# -gt 0; then
+              version=$1
+            else
+              die "Please provide a version name"
+            fi
+            shift
+            ;;
+    --version*)
+            version=`echo $1 | sed -e 's/^[^=]*=//g'`
+            shift
+            ;;
+    -d)
+            shift
+            if test $# -gt 0; then
+              dir=$1
+            else
+              die "Please provide a version"
+            fi
+            shift
+            ;;
+    --dir*)
+            dir=`echo $1 | sed -e 's/^[^=]*=//g'`
+            shift
+            ;;
+    *)
+            die "Unknown param $1"
+            break
+            ;;
+  esac
+done
+
+test -z "$version" && version="$(last_version)"
+test -z "$version" && {
+  die "Unable to get ${BINARY_NAME} version. You can still try to download it manually from $RELEASES_URL."
+}
+test -z "$dir" &&  dir="$(mktemp -d --suffix=-${BINARY_NAME}-${version})"
+
+download ${version}
+tar -C "$dir" -xzf "$TAR_FILE" ${BINARY_NAME}
+
+echo "Downloaded ${BINARY_NAME} binary ($version) to $dir"
+echo "Make sure it's on your \$PATH."