diff --git a/cd.sh b/cd.sh
index e4796f3..e50c76f 100644
--- a/cd.sh
+++ b/cd.sh
@@ -1,3 +1,5 @@
+#! /usr/bin/env bash
+
 CD_DNS_SERVERS=(
 '9.9.9.9'
 )
@@ -21,77 +23,180 @@ case "${CD_OS_NAME}" in
         exit 1
     ;;
 esac
+CD_STEP=0
 
-function split {
-    [ "${1}" ] && echo "
-${1}
+function cd_step {
+    if [ "${1}" ] ; then
+        ((CD_STEP++))
+        echo "
+ ↕ ${CD_STEP} ↔ ${1}
 "
+    fi
 }
 
-split " 1/14 set name servers"
-for server in "${CD_DNS_SERVERS[@]}" ; do
-    echo "nameserver ${server}" \
-    >> "${CD_DNS_FILE}" \
-    || exit
-done
+function cd_write {
+local file="${1}"
+local text="${2}"
+    if [ "${file}" ] ; then
+        echo -n "${text}" \
+        > "${file}" \
+        || exit
+    fi
+}
 
-split " 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
-split " 3/14 configure package repositories"
-echo -n "\
+function cd_set_dns_resolving {
+local server
+local text=''
+    cd_step "${FUNCNAME}"
+    for server in "${CD_DNS_SERVERS[@]}" ; do
+        text+="nameserver ${server}
+"
+    done
+    cd_write "${CD_DNS_FILE}" "${text}"
+}
+
+function cd_set_packages_repositories {
+    cd_step "${FUNCNAME}"
+    case "${CD_OS_NAME}" in
+        'debian')
+            cd_write '/etc/apt/sources.list' "\
 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
+"
+        ;;
+        *) exit 1 ;;
+    esac
+}
 
-split " 4/14 disable package verification"
-echo -n "\
+function cd_set_packages_configuration {
+    cd_step "${FUNCNAME}"
+    case "${CD_OS_NAME}" in
+        'debian')
+            cd_write '/etc/apt/apt.conf.d/apt.conf' "\
+Acquire::Check-Valid-Until True;
+APT::Get::Show-Versions True;
+APT::Install-Recommends False;
+APT::Install-Suggests False;
+Dir::Etc::SourceParts \"\";
+"
+        ;;
+        *) exit 1 ;;
+    esac
+}
+
+function cd_set_https_verification_off {
+    cd_step "${FUNCNAME}"
+    case "${CD_OS_NAME}" in
+        'debian')
+            cd_write '/etc/apt/apt.conf.d/https' "\
 Acquire::https::Verify-Peer False;
-" > '/etc/apt/apt.conf.d/https' \
-|| exit
-split " 5/14 update package catalog"
-apt-get update \
-|| exit
-split " 6/14 install CA certificates package"
-apt-get install --yes 'ca-certificates' \
-|| exit
-split " 7/14 enable package verification"
-rm '/etc/apt/apt.conf.d/https' \
-|| exit
+"
+        ;;
+        *) exit 1 ;;
+    esac
+}
 
-split " 8/14 update package catalog"
-apt-get update \
-|| exit
-split " 9/14 upgrade packages"
-apt-get upgrade --yes \
-|| exit
+function cd_update_packages_catalog {
+    cd_step "${FUNCNAME}"
+    case "${CD_OS_NAME}" in
+        'debian') apt-get update || exit ;;
+        *) exit 1 ;;
+    esac
+}
 
-split "10/14 install Git"
-apt-get install --yes 'git' \
-|| exit
+function cd_install_package {
+    if [ "${1}" ] ; then
+        case "${CD_OS_NAME}" in
+            'debian') apt-get install --yes "${1}" || exit ;;
+            *) exit 1 ;;
+        esac
+    fi
+}
+
+function cd_install_ca {
+    cd_step "${FUNCNAME}"
+    case "${CD_OS_NAME}" in
+        'debian') cd_install_package 'ca-certificates' ;;
+        *) exit 1 ;;
+    esac
+}
+
+function cd_install_git {
+    cd_step "${FUNCNAME}"
+    case "${CD_OS_NAME}" in
+        'debian') cd_install_package 'git' ;;
+        *) exit 1 ;;
+    esac
+}
+
+function cd_install_packages_tools {
+    cd_step "${FUNCNAME}"
+    case "${CD_OS_NAME}" in
+        'debian') cd_install_package 'apt-utils' ;;
+        *) exit 1 ;;
+    esac
+}
+
+function cd_install_python {
+    cd_step "${FUNCNAME}"
+    case "${CD_OS_NAME}" in
+        'debian') cd_install_package 'python3' ;;
+        *) exit 1 ;;
+    esac
+}
+
+function cd_set_https_verification_on {
+    cd_step "${FUNCNAME}"
+    case "${CD_OS_NAME}" in
+        'debian') rm '/etc/apt/apt.conf.d/https' ;;
+        *) exit 1 ;;
+    esac
+}
+
+function cd_upgrade_packages {
+    cd_step "${FUNCNAME}"
+    case "${CD_OS_NAME}" in
+        'debian') apt-get upgrade --yes || exit ;;
+        *) exit 1 ;;
+    esac
+}
+
+function cd_clean_packages_cache {
+    cd_step "${FUNCNAME}"
+    case "${CD_OS_NAME}" in
+        'debian') apt-get clean || exit ;;
+        *) exit 1 ;;
+    esac
+}
+
+function cd_main {
+    cd_set_dns_resolving
+    cd_set_packages_repositories
+    cd_set_packages_configuration
+    cd_set_https_verification_off
+    cd_update_packages_catalog
+    cd_install_packages_tools
+    cd_install_ca
+    cd_set_https_verification_on
+    cd_update_packages_catalog
+    cd_upgrade_packages
+    cd_install_git
+    cd_install_python
+    cd_clean_packages_cache
 
 DIRECTORY="$(mktemp --directory)" \
 || exit
-split "11/14 clone Continuous Delivery"
+cd_step "clone Continuous Delivery"
 git clone \
 "${GITHUB_SERVER_URL}/${CD_REPOSITORY}" \
 "${DIRECTORY}" \
 || exit
 
-split "12/14 install Python"
-apt-get install --yes 'python3' \
-|| exit
-split "13/14 clean package cache"
-apt-get clean \
-|| exit
-split "14/14 bootstrap"
+cd_step "bootstrap"
 "${DIRECTORY}/bootstrap.sh"
+
+}
+
+cd_main