Add direnv installer script

packages/direnv.sh

@@ -0,0 +1,109 @@
+#!/usr/bin/env bash
+#
+# A good old bash | curl script for direnv.
+#
+set -euo pipefail
+
+{ # Prevent execution if this script was only partially downloaded
+
+  log() {
+    echo "[installer] $*" >&2
+  }
+
+  die() {
+    log "$@"
+    exit 1
+  }
+
+  at_exit() {
+    ret=$?
+    if [[ $ret -gt 0 ]]; then
+      log "the script failed with error $ret.\n" \
+        "\n" \
+        "To report installation errors, submit an issue to\n" \
+        "    https://github.com/direnv/direnv/issues/new/choose"
+    fi
+    exit "$ret"
+  }
+  trap at_exit EXIT
+
+  kernel=$(uname -s | tr "[:upper:]" "[:lower:]")
+  case "${kernel}" in
+    mingw*)
+      kernel=windows
+      ;;
+  esac
+  case "$(uname -m)" in
+    x86_64)
+      machine=amd64
+      ;;
+    i686 | i386)
+      machine=386
+      ;;
+    aarch64 | arm64)
+      machine=arm64
+      ;;
+    *)
+      die "Machine $(uname -m) not supported by the installer.\n" \
+        "Go to https://direnv for alternate installation methods."
+      ;;
+  esac
+  log "kernel=$kernel machine=$machine"
+
+  : "${use_sudo:=}"
+  : "${bin_path:=}"
+
+  if [[ -z "$bin_path" ]]; then
+    log "bin_path is not set, you can set bin_path to specify the installation path"
+    log "e.g. export bin_path=/path/to/installation before installing"
+    log "looking for a writeable path from PATH environment variable"
+    for path in $(echo "$PATH" | tr ':' '\n'); do
+      if [[ -w $path ]]; then
+        bin_path=$path
+        break
+      fi
+    done
+  fi
+  if [[ -z "$bin_path" ]]; then
+    die "did not find a writeable path in $PATH"
+  fi
+  echo "bin_path=$bin_path"
+
+  if [[ -n "${version:-}" ]]; then
+    release="tags/${version}"
+  else
+    release="latest"
+  fi
+  echo "release=$release"
+
+  log "looking for a download URL"
+  download_url=$(
+    curl -fL "https://api.github.com/repos/direnv/direnv/releases/$release" \
+    | grep browser_download_url \
+    | cut -d '"' -f 4 \
+    | grep "direnv.$kernel.$machine"
+  )
+  echo "download_url=$download_url"
+
+  log "downloading"
+  curl -o "$bin_path/direnv" -fL "$download_url"
+  chmod a+x "$bin_path/direnv"
+
+  cat <<DONE
+
+The direnv binary is now available in:
+
+    $bin_path/direnv
+
+The last step is to configure your shell to use it. For example for bash, add
+the following lines at the end of your ~/.bashrc:
+
+    eval "\$(direnv hook bash)"
+
+Then restart the shell.
+
+For other shells, see https://direnv.net/docs/hook.html
+
+Thanks!
+DONE
+}