diff --git a/install2.sh b/install2.sh
index 296f0da..59d3ec5 100755
--- a/install2.sh
+++ b/install2.sh
@@ -1,5 +1,4 @@
-#!/usr/bin/bash -E
-# shellcheck disable=all
+#!/usr/bin/env bash
 
 ## CONSTANTS
 
@@ -7,11 +6,23 @@ MAIN_TAR_GZ_URL="https://git.artcode.re/miaou/miaou-bash/archive/main.tar.gz"
 
 ## FUNCTIONS
 
-function bootstrap {
-  cd "$(mktemp -d)" || exit 3
-  curl -s -O $MAIN_TAR_GZ_URL
-  tar -xzf main.tar.gz --directory $(dirname "$MIAOU_BASH_DIR")
-  . "$MIAOU_BASH_DIR"/bin/miaou-bash "$MIAOU_BASH_DIR/lib/initiate.bash"
+function upgrade {
+  source_miaou_lib self_upgrade
+}
+
+function install {
+  [[ "$UID" -ne 0 ]] && sudo -vp 'SUDO privilege required: '
+
+  MIAOU_BASH_DIR=/opt/miaou-bash
+  export MIAOU_BASH_DIR
+  cd /tmp
+
+  curl -sO $MAIN_TAR_GZ_URL
+  sudo tar -xzf main.tar.gz --directory $(dirname "$MIAOU_BASH_DIR")
+  source_miaou_lib initiate
+
+  source /etc/profile
+  echo "miaou-bash successfully installed"
 }
 
 function assert_supported_distro {
@@ -25,26 +36,19 @@ function assert_supported_distro {
 }
 
 function once_installed {
-  [[ -d "$MIAOU_BASH_DIR" &&
+  [[ -v MIAOU_BASH_DIR && -d "$MIAOU_BASH_DIR" &&
     -L /etc/inputrc &&
     "$(readlink /etc/inputrc)" == "$MIAOU_BASH_DIR"/etc/inputrc ]]
 }
 
+function source_miaou_lib {
+  . "$MIAOU_BASH_DIR"/bin/miaou-bash "$MIAOU_BASH_DIR/lib/"$1".bash"
+}
+
 ## MAIN
 
-set -Eeuo pipefail
+# source <(curl -s https://git.artcode.re/miaou/miaou-bash/raw/branch/main/install2.sh)
 
+set -Eeuo pipefail
 assert_supported_distro
-deployment_type_adjective="${1:-installed}"
-[[ ! -v MIAOU_BASH_DIR ]] && MIAOU_BASH_DIR=/opt/miaou-bash && export MIAOU_BASH_DIR
-
-if [[ "$UID" -ne 0 ]]; then
-  sudo -vp 'root privilege required (SUDO): '
-  curl -s https://git.artcode.re/miaou/miaou-bash/raw/branch/main/install2.sh | sudo bash
-  source /etc/profile
-elif once_installed; then
-  . "$MIAOU_BASH_DIR"/bin/miaou-bash "$MIAOU_BASH_DIR/lib/self-upgrade.bash"
-else
-  bootstrap
-  echo "miaou-bash successfully $deployment_type_adjective"
-fi
+once_installed && upgrade || install