Fix curl|bash race condition in install script

Wrap entire script in main() function to ensure bash reads the complete
script before executing any of it. Previously, the inner curl call to
fetch the release tag could interfere with the outer curl|bash pipe,
causing "Failure writing output to destination" errors.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: rawwerks

install.sh

@@ -1,87 +1,93 @@
 #!/usr/bin/env bash
+# Wrapped in main() to prevent curl|bash race condition
 set -euo pipefail
 
-REPO="rawwerks/dirpack"
-API_URL="https://api.github.com/repos/${REPO}/releases/latest"
-
-fail() {
-  echo "install.sh: $*" >&2
-  exit 1
-}
-
-require_cmd() {
-  command -v "$1" >/dev/null 2>&1 || fail "missing required command: $1"
+main() {
+  REPO="rawwerks/dirpack"
+  API_URL="https://api.github.com/repos/${REPO}/releases/latest"
+
+  fail() {
+    echo "install.sh: $*" >&2
+    exit 1
+  }
+
+  require_cmd() {
+    command -v "$1" >/dev/null 2>&1 || fail "missing required command: $1"
+  }
+
+  require_cmd curl
+  require_cmd uname
+
+  tag="$(
+    curl -fsSL "$API_URL" | grep -m1 '"tag_name"' | sed -E 's/.*"tag_name": *"([^"]+)".*/\1/'
+  )"
+
+  if [ -z "$tag" ]; then
+    fail "could not determine latest release tag"
+  fi
+
+  os="$(uname -s)"
+  case "$os" in
+    Linux) os="linux" ;;
+    Darwin) os="macos" ;;
+    *) fail "unsupported OS: $os" ;;
+  esac
+
+  arch="$(uname -m)"
+  case "$arch" in
+    x86_64|amd64) arch="x86_64" ;;
+    arm64|aarch64) arch="aarch64" ;;
+    *) fail "unsupported architecture: $arch" ;;
+  esac
+
+  asset="dirpack-${os}-${arch}"
+  url="https://github.com/${REPO}/releases/download/${tag}/${asset}"
+
+  tmpfile="$(mktemp)"
+  cleanup() {
+    rm -f "$tmpfile"
+  }
+  trap cleanup EXIT
+
+  echo "Downloading ${asset} from ${url}"
+  curl -fL --progress-bar "$url" -o "$tmpfile" || fail "download failed"
+
+  chmod +x "$tmpfile"
+
+  install_dir="${HOME}/.local/bin"
+  use_sudo=false
+
+  if [ ! -d "$install_dir" ]; then
+    mkdir -p "$install_dir" 2>/dev/null || true
+  fi
+
+  if [ ! -w "$install_dir" ]; then
+    install_dir="/usr/local/bin"
+    use_sudo=true
+  fi
+
+  dest="${install_dir}/dirpack"
+
+  if [ "$use_sudo" = true ]; then
+    require_cmd sudo
+    sudo mv "$tmpfile" "$dest"
+  else
+    mv "$tmpfile" "$dest"
+  fi
+
+  version="$("$dest" --version 2>/dev/null || true)"
+  if [ -z "$version" ]; then
+    fail "dirpack did not run successfully after install"
+  fi
+
+  echo "Installed ${version} to ${dest}"
+
+  if ! command -v dirpack >/dev/null 2>&1; then
+    echo "Note: ${install_dir} is not on your PATH."
+    echo "Add this to your shell profile:"
+    echo "  export PATH=\"${install_dir}:\$PATH\""
+  fi
 }
 
-require_cmd curl
-require_cmd uname
-
-tag="$(
-  curl -fsSL "$API_URL" | grep -m1 '"tag_name"' | sed -E 's/.*"tag_name": *"([^"]+)".*/\1/'
-)"
-
-if [ -z "$tag" ]; then
-  fail "could not determine latest release tag"
-fi
-
-os="$(uname -s)"
-case "$os" in
-  Linux) os="linux" ;;
-  Darwin) os="macos" ;;
-  *) fail "unsupported OS: $os" ;;
-esac
-
-arch="$(uname -m)"
-case "$arch" in
-  x86_64|amd64) arch="x86_64" ;;
-  arm64|aarch64) arch="aarch64" ;;
-  *) fail "unsupported architecture: $arch" ;;
-esac
-
-asset="dirpack-${os}-${arch}"
-url="https://github.com/${REPO}/releases/download/${tag}/${asset}"
-
-tmpfile="$(mktemp)"
-cleanup() {
-  rm -f "$tmpfile"
-}
-trap cleanup EXIT
-
-echo "Downloading ${asset} from ${url}"
-curl -fL --progress-bar "$url" -o "$tmpfile" || fail "download failed"
-
-chmod +x "$tmpfile"
-
-install_dir="${HOME}/.local/bin"
-use_sudo=false
-
-if [ ! -d "$install_dir" ]; then
-  mkdir -p "$install_dir" 2>/dev/null || true
-fi
-
-if [ ! -w "$install_dir" ]; then
-  install_dir="/usr/local/bin"
-  use_sudo=true
-fi
-
-dest="${install_dir}/dirpack"
-
-if [ "$use_sudo" = true ]; then
-  require_cmd sudo
-  sudo mv "$tmpfile" "$dest"
-else
-  mv "$tmpfile" "$dest"
-fi
-
-version="$("$dest" --version 2>/dev/null || true)"
-if [ -z "$version" ]; then
-  fail "dirpack did not run successfully after install"
-fi
-
-echo "Installed ${version} to ${dest}"
-
-if ! command -v dirpack >/dev/null 2>&1; then
-  echo "Note: ${install_dir} is not on your PATH."
-  echo "Add this to your shell profile:"
-  echo "  export PATH=\"${install_dir}:\$PATH\""
-fi
+# Call main only after entire script is downloaded
+main "$@"