diff --git a/bootstrap.sh b/bootstrap.sh
index e6a0466..dd40508 100755
--- a/bootstrap.sh
+++ b/bootstrap.sh
@@ -1,4 +1,3 @@
-#! /usr/bin/env bash
 FILE="$(realpath "${BASH_SOURCE[0]}")"
 ROOT="$(dirname "${FILE}")"
 
@@ -9,6 +8,7 @@ KEY_PATH="${KEY_DIRECTORY}/id_${KEY_ALGORITHM}"
 KEY_PUBLIC='AAAAC3NzaC1lZDI1NTE5AAAAIPHCNcgHlQoiNTXfnUZYvHz9OZwYsmBCrSSV7a7Zche5'
 PACKAGES=(
 'openssh-client'
+'python3'
 'rsync'
 'tree'
 )
@@ -40,3 +40,6 @@ echo "${SERVER} ssh-${KEY_ALGORITHM} ${KEY_PUBLIC}" \
 # packages
 apt-get install --yes "${PACKAGES[@]}" \
 || exit
+
+# remove
+rm --force --recursive "${ROOT}"
diff --git a/cd.sh b/cd.sh
index c362a84..3dae9f5 100644
--- a/cd.sh
+++ b/cd.sh
@@ -1,100 +1,33 @@
 NAMESERVERS=(
 '9.9.9.9'
 )
+PACKAGES=(
+'ca-certificates'
+'git'
+)
 REPOSITORY='rwx.work/cd'
 
-echo "
- 1/14 set name servers
-"
 for nameserver in "${NAMESERVERS[@]}" ; do
     echo "nameserver ${nameserver}" \
     >> '/etc/resolv.conf' \
     || exit
 done
 
-echo "
- 2/14 configure package manager
-"
 echo -n "\
-Acquire::Check-Valid-Until True;
 APT::Get::Show-Versions True;
 APT::Install-Recommends False;
 APT::Install-Suggests False;
-Dir::Etc::SourceParts '';
 " > '/etc/apt/apt.conf.d/apt.conf' \
 || exit
-echo "
- 3/14 configure package repositories
-"
-echo -n "\
-deb https://deb.debian.org/debian bookworm main
-deb https://deb.debian.org/debian bookworm-backports main
-deb https://deb.debian.org/debian bookworm-updates main
-deb https://deb.debian.org/debian-security bookworm-security main
-" > '/etc/apt/sources.list' \
-|| exit
-
-echo "
- 4/14 disable package verification
-"
-echo -n "\
-Acquire::https::Verify-Peer False;
-" > '/etc/apt/apt.conf.d/https' \
-|| exit
-echo "
- 5/14 update package catalog
-"
 apt-get update \
 || exit
-echo "
- 6/14 install CA certificates package
-"
-apt-get install --yes 'ca-certificates' \
-|| exit
-echo "
- 7/14 enable package verification
-"
-rm '/etc/apt/apt.conf.d/https' \
-|| exit
-
-echo "
- 8/14 update package catalog
-"
-apt-get update \
-|| exit
-echo "
- 9/14 upgrade packages
-"
-apt-get upgrade --yes \
-|| exit
-
-echo "
-10/14 install Git
-"
-apt-get install --yes 'git' \
+apt-get install --yes "${PACKAGES[@]}" \
 || exit
 
 DIRECTORY="$(mktemp --directory)" \
 || exit
-echo "
-11/14 clone Continuous Delivery
-"
 git clone \
 "${GITHUB_SERVER_URL}/${REPOSITORY}" \
 "${DIRECTORY}" \
 || exit
-
-echo "
-12/14 install Python
-"
-apt-get install --yes 'python3' \
-|| exit
-echo "
-13/14 clean package cache
-"
-apt-get clean \
-|| exit
-echo "
-14/14 bootstrap
-"
 "${DIRECTORY}/bootstrap.sh"