auto-update.patch

diff --git a/imgur-screenshot b/imgur-screenshot
index 4a9c8b9..a1347b6 100755
--- a/imgur-screenshot
+++ b/imgur-screenshot
@@ -82,6 +82,7 @@ load_default_config() {
   declare -g EDIT="false"
   declare -g AUTO_DELETE
   declare -g KEEP_FILE="true"
+  declare -g AUTO_UPDATE="false"

   # NOTICE: if you make changes here, also edit the docs at
   # https://github.com/jomo/imgur-screenshot/wiki/Config
@@ -119,7 +120,7 @@ parse_args() {
       echo "  -k, --keep-file <true|false> Override 'KEEP_FILE' config"
       echo "  -d, --auto-delete <s>        Automatically delete image after <s> seconds"
       echo ""
-      echo "  -u, --update                 Check for updates, exit"
+      echo "  -u, --update                 Check for a newer version, install if available, exit"
       echo ""
       echo "  file                         Upload file instead of taking a screenshot"
       exit 0;;
@@ -165,6 +166,7 @@ parse_args() {
       AUTO_DELETE="${2}"
       shift 2;;
     -u | --update)
+      AUTO_UPDATE="true"
       check_for_update
       exit 0;;
     *)
@@ -287,6 +289,13 @@ check_for_update() {
       echo "Version ${remote_version} is available (You have ${CURRENT_VERSION})"
       notify ok "Update found" "Version ${remote_version} is available (You have ${CURRENT_VERSION}). https://github.com/jomo/imgur-screenshot"
       echo "Check https://github.com/jomo/imgur-screenshot/releases/${remote_version} for more info."
+
+      if [ "${AUTO_UPDATE}" == "true" ]; then
+        run_update "${remote_version}"
+      else
+        echo "Use --update to install the new version"
+      fi
+
     elif [ -z "${CURRENT_VERSION}" ] || [ -z "${remote_version}" ]; then
       echo "Invalid empty version string"
       echo "Current (local) version: '${CURRENT_VERSION}'"
@@ -299,6 +308,33 @@ check_for_update() {
   fi
 }

+run_update() {
+  local remote_version remote_script self script_path tmp_script bak_script
+
+  set -o errexit
+
+  remote_version="${1}"
+  remote_script="https://github.com/jomo/imgur-screenshot/releases/download/${remote_version}/imgur-screenshot"
+  tmp_script="$(mktemp)"
+  bak_script="$(mktemp)"
+
+  # determine this script's location
+  self="$(command -v "${0}")"
+  script_path="$(readlink "${self}" || echo "${self}")"
+
+  # Download latest version
+  echo "Downloading and installing latest version..."
+  curl --compressed -fsSL --stderr - -'#' "${remote_script}" > "${tmp_script}"
+  if [ ! "${?}" -eq "0" ]; then
+    echo "Update failed:" >&2
+    cat "${tmp_script}" >&2
+    exit 1
+  fi
+  mv -v "${script_path}" "${bak_script}.bak"
+  mv -v "${tmp_script}" "${script_path}"
+  echo "Successfully updated to ${remote_version}."
+}
+
 check_oauth2_client_secrets() {
   if [ -z "${CLIENT_ID}" ] || [ -z "${CLIENT_SECRET}" ]; then
     echo "Your CLIENT_ID and CLIENT_SECRET are not set."