feat(script): add installer for git-cliff binary

- Introduce a bash script to install the git-cliff binary
- Support fetching the latest or specific versions from GitHub
- Ensure compatibility with x86_64 Linux systems
- Validate required tools and handle installation errors

install-git-cliff.sh

@@ -0,0 +1,82 @@
+#!/usr/bin/env bash
+# install-git-cliff.sh – fetches the latest or specified git-cliff binary (x86_64)
+# Usage: sudo ./install-git-cliff.sh        # latest version
+#        sudo ./install-git-cliff.sh 2.9.0  # specific version
+#        sudo ./install-git-cliff.sh -h     # help
+set -euo pipefail
+
+REPO="orhun/git-cliff"
+ARCH_OS="x86_64-unknown-linux-gnu"
+INSTALL_DIR="/usr/local/bin"
+VERSION="${1:-latest}"
+
+# 0 Handle -h/--help option
+if [[ "$VERSION" == "-h" || "$VERSION" == "--help" ]]; then
+  cat <<EOF
+install-git-cliff.sh – Installs the git-cliff binary (x86_64)
+
+Usage:
+  sudo ./install-git-cliff.sh
+      Install the latest version
+
+  sudo ./install-git-cliff.sh <version>
+      Install a specific version (e.g. 2.9.0)
+
+  sudo ./install-git-cliff.sh -h | --help
+      Show this help message
+
+This script downloads the appropriate release archive from GitHub,
+extracts it, and installs the 'git-cliff' binary to ${INSTALL_DIR}.
+EOF
+  exit 0
+fi
+
+# 1 Check for required tools
+need() { command -v "$1" >/dev/null || { echo "$1 is missing"; exit 1; }; }
+need curl; need tar; need grep; need sed; need awk; need jq
+
+# 2 Determine version → Fetch release JSON
+if [[ "$VERSION" == "latest" ]]; then
+  API_URL="https://api.github.com/repos/${REPO}/releases/latest"
+else
+  API_URL="https://api.github.com/repos/${REPO}/releases/tags/v${VERSION}"
+fi
+
+echo "🔍 Fetching release info ($API_URL)…"
+JSON=$(curl -fsSL "$API_URL") || {
+  echo "❌ Failed to fetch release info"
+  exit 1
+}
+
+VERSION=$(jq -r '.tag_name' <<< "$JSON") || {
+  echo "❌ Could not extract version"
+  exit 1
+}
+
+ASSET_URL=$(jq -r '.assets[]?.browser_download_url' <<< "$JSON" |
+  grep "${ARCH_OS}\.tar" | head -n1)
+
+if [[ -z "$ASSET_URL" ]]; then
+  echo "❌ Matching asset not found for architecture ${ARCH_OS}"
+  exit 1
+fi
+
+ASSET_FILE=$(basename "$ASSET_URL")
+echo "📦 Downloading git-cliff v${VERSION} (${ASSET_FILE}) …"
+TMP=$(mktemp -d)
+curl -#L -o "${TMP}/${ASSET_FILE}" "$ASSET_URL"
+
+# 3 Extract based on file extension
+case "$ASSET_FILE" in
+  *.tar.gz|*.tgz) tar -C "$TMP" -xzf "${TMP}/${ASSET_FILE}" ;;
+  *.tar.xz)       tar -C "$TMP" -xJf "${TMP}/${ASSET_FILE}" ;;
+  *.zip)          need unzip; unzip -q "${TMP}/${ASSET_FILE}" -d "$TMP" ;;
+  *) echo "❌ Unknown archive format: $ASSET_FILE"; exit 1 ;;
+esac
+
+# 4 Locate and install binary
+BIN_PATH=$(find "$TMP" -type f -name git-cliff -perm -u+x | head -n1)
+[[ -z "$BIN_PATH" ]] && { echo "❌ Binary not found"; exit 1; }
+
+sudo install -m755 "$BIN_PATH" "${INSTALL_DIR}/git-cliff"
+echo "✅ git-cliff $(git-cliff --version) installed in ${INSTALL_DIR}"