diff --git a/kiauh.sh b/kiauh.sh
index fbeb031..f8d2bd7 100755
--- a/kiauh.sh
+++ b/kiauh.sh
@@ -23,8 +23,10 @@ for script in "${KIAUH_SRCDIR}/scripts/ui/"*.sh; do . "${script}"; done
 
 function update_kiauh() {
   status_msg "Updating KIAUH ..."
+
   cd "${KIAUH_SRCDIR}"
   git reset --hard && git pull
+
   ok_msg "Update complete! Please restart KIAUH."
   exit 0
 }
@@ -36,14 +38,18 @@ function update_kiauh() {
 function kiauh_update_avail() {
   [[ ! -d "${KIAUH_SRCDIR}/.git" ]] && return
   local origin head
+
   cd "${KIAUH_SRCDIR}"
+
   ### abort if not on master branch
   ! git branch -a | grep -q "\* master" && return
+
   ### compare commit hash
   git fetch -q
   origin=$(git rev-parse --short=8 origin/master)
   head=$(git rev-parse --short=8 HEAD)
-  if [[ ${origin} != ${head} ]]; then
+
+  if [[ ${origin} != "${head}" ]]; then
     echo "true"
   fi
 }
diff --git a/scripts/backup.sh b/scripts/backup.sh
index bb89c5a..c7473d5 100755
--- a/scripts/backup.sh
+++ b/scripts/backup.sh
@@ -12,28 +12,30 @@
 set -e
 
 function get_date() {
+  local current_date
   current_date=$(date +"%y%m%d-%H%M")
   echo "${current_date}"
 }
 
 function check_for_backup_dir() {
-  [ -d "${BACKUP_DIR}" ] && return
+  [[ -d ${BACKUP_DIR} ]] && return
+
   status_msg "Create KIAUH backup directory ..."
   mkdir -p "${BACKUP_DIR}" && ok_msg "Directory created!"
 }
 
 function backup_before_update() {
   read_kiauh_ini "${FUNCNAME[0]}"
-  # shellcheck disable=SC2154
   local state="${backup_before_update}"
-  [ "${state}" = "false" ] && return
+  [[ ${state} = "false" ]] && return
   backup_"${1}"
 }
 
 function backup_printer_cfg() {
   check_for_backup_dir
   local current_date
-  if [ -f "${PRINTER_CFG}" ]; then
+
+  if [[ -f "${PRINTER_CFG}" ]]; then
     current_date=$(get_date)
     status_msg "Timestamp: ${current_date}"
     status_msg "Create backup of printer.cfg ..."
@@ -45,14 +47,18 @@ function backup_printer_cfg() {
 
 function backup_klipper_config_dir() {
   check_for_backup_dir
-  local current_date
-  if [ -d "${KLIPPER_CONFIG}" ]; then
+  local current_date config_folder_name
+
+  if [[ -d "${KLIPPER_CONFIG}" ]]; then
     current_date=$(get_date)
+    config_folder_name="$(echo "${KLIPPER_CONFIG}" | rev | cut -d"/" -f1 | rev)"
+
     status_msg "Timestamp: ${current_date}"
     status_msg "Create backup of the Klipper config directory ..."
-    config_folder_name="$(echo "${KLIPPER_CONFIG}" | rev | cut -d"/" -f1 | rev)"
+
     mkdir -p "${BACKUP_DIR}/${config_folder_name}/${current_date}"
     cp -r "${KLIPPER_CONFIG}" "${_}"
+
     print_confirm "Configuration directory backup complete!"
   else
     ok_msg "No config directory found! Skipping backup ..."
@@ -62,18 +68,21 @@ function backup_klipper_config_dir() {
 function backup_moonraker_database() {
   check_for_backup_dir
   local current_date databases target_dir
-
   databases=$(find "${HOME}" -maxdepth 1 -type d -regextype posix-extended -regex "${HOME}/.moonraker_database(_[^0])?[0-9]*" | sort)
-  if [ -n "${databases}" ]; then
+
+  if [[ -n "${databases}" ]]; then
     current_date=$(get_date)
     target_dir="${BACKUP_DIR}/moonraker_database_backup/${current_date}"
+
     status_msg "Timestamp: ${current_date}"
     mkdir -p "${target_dir}"
+
     for database in ${databases}; do
       status_msg "Create backup of ${database} ..."
       cp -r "${database}" "${target_dir}"
       ok_msg "Done!"
     done
+
     print_confirm "Moonraker database backup complete!"
   else
     print_error "No Moonraker database found! Skipping backup ..."
@@ -83,7 +92,8 @@ function backup_moonraker_database() {
 
 function backup_klipper() {
   local current_date
-  if [ -d "${KLIPPER_DIR}" ] && [ -d "${KLIPPY_ENV}" ]; then
+
+  if [[ -d ${KLIPPER_DIR} && -d ${KLIPPY_ENV} ]]; then
     status_msg "Creating Klipper backup ..."
     check_for_backup_dir
     current_date=$(get_date)
@@ -92,13 +102,14 @@ function backup_klipper() {
     cp -r "${KLIPPER_DIR}" "${_}" && cp -r "${KLIPPY_ENV}" "${_}"
     print_confirm "Klipper backup complete!"
   else
-    print_error "Can't backup klipper and/or klipper-env directory! Not found!"
+    print_error "Can't back up 'klipper' and/or 'klipper-env' directory! Not found!"
   fi
 }
 
 function backup_mainsail() {
   local current_date
-  if [ -d "${MAINSAIL_DIR}" ]; then
+
+  if [[ -d ${MAINSAIL_DIR} ]]; then
     status_msg "Creating Mainsail backup ..."
     check_for_backup_dir
     current_date=$(get_date)
@@ -107,13 +118,14 @@ function backup_mainsail() {
     cp -r "${MAINSAIL_DIR}" "${_}"
     print_confirm "Mainsail backup complete!"
   else
-    print_error "Can't backup mainsail directory! Not found!"
+    print_error "Can't back up 'mainsail' directory! Not found!"
   fi
 }
 
 function backup_fluidd() {
   local current_date
-  if [ -d "${FLUIDD_DIR}" ]; then
+
+  if [[ -d ${FLUIDD_DIR} ]]; then
     status_msg "Creating Fluidd backup ..."
     check_for_backup_dir
     current_date=$(get_date)
@@ -122,13 +134,14 @@ function backup_fluidd() {
     cp -r "${FLUIDD_DIR}" "${_}"
     print_confirm "Fluidd backup complete!"
   else
-    print_error "Can't backup fluidd directory! Not found!"
+    print_error "Can't back up 'fluidd' directory! Not found!"
   fi
 }
 
 function backup_moonraker() {
   local current_date
-  if [ -d "${MOONRAKER_DIR}" ] && [ -d "${MOONRAKER_ENV}" ]; then
+
+  if [[ -d ${MOONRAKER_DIR} && -d ${MOONRAKER_ENV} ]]; then
     status_msg "Creating Moonraker backup ..."
     check_for_backup_dir
     current_date=$(get_date)
@@ -137,13 +150,14 @@ function backup_moonraker() {
     cp -r "${MOONRAKER_DIR}" "${_}" && cp -r "${MOONRAKER_ENV}" "${_}"
     print_confirm "Moonraker backup complete!"
   else
-    print_error "Can't backup moonraker and/or moonraker-env directory! Not found!"
+    print_error "Can't back up moonraker and/or moonraker-env directory! Not found!"
   fi
 }
 
 function backup_octoprint() {
   local current_date
-  if [ -d "${OCTOPRINT_DIR}" ] && [ -d "${OCTOPRINT_CFG_DIR}" ]; then
+
+  if [[ -d ${OCTOPRINT_DIR} && -d ${OCTOPRINT_CFG_DIR} ]]; then
     status_msg "Creating OctoPrint backup ..."
     check_for_backup_dir
     current_date=$(get_date)
@@ -152,13 +166,13 @@ function backup_octoprint() {
     cp -r "${OCTOPRINT_DIR}" "${_}" && cp -r "${OCTOPRINT_CFG_DIR}" "${_}"
     print_confirm " OctoPrint backup complete!"
   else
-    print_error "Can't backup OctoPrint and/or .octoprint directory!\n Not found!"
+    print_error "Can't back up OctoPrint and/or .octoprint directory!\n Not found!"
   fi
 }
 
 function backup_klipperscreen() {
   local current_date
-  if [ -d "${KLIPPERSCREEN_DIR}" ] ; then
+  if [[ -d ${KLIPPERSCREEN_DIR} ]] ; then
     status_msg "Creating KlipperScreen backup ..."
     check_for_backup_dir
     current_date=$(get_date)
@@ -167,13 +181,14 @@ function backup_klipperscreen() {
     cp -r "${KLIPPERSCREEN_DIR}" "${_}"
     print_confirm "KlipperScreen backup complete!"
   else
-    print_error "Can't backup KlipperScreen directory!\n Not found!"
+    print_error "Can't back up KlipperScreen directory!\n Not found!"
   fi
 }
 
 function backup_telegram_bot() {
   local current_date
-  if [ -d "${TELEGRAM_BOT_DIR}" ] ; then
+
+  if [[ -d ${TELEGRAM_BOT_DIR} ]] ; then
     status_msg "Creating MoonrakerTelegramBot backup ..."
     check_for_backup_dir
     current_date=$(get_date)
@@ -182,6 +197,6 @@ function backup_telegram_bot() {
     cp -r "${TELEGRAM_BOT_DIR}" "${_}"
     print_confirm "MoonrakerTelegramBot backup complete!"
   else
-    print_error "Can't backup MoonrakerTelegramBot directory!\n Not found!"
+    print_error "Can't back up MoonrakerTelegramBot directory!\n Not found!"
   fi
 }
diff --git a/scripts/flash_klipper.sh b/scripts/flash_klipper.sh
index 37477f7..55ca359 100644
--- a/scripts/flash_klipper.sh
+++ b/scripts/flash_klipper.sh
@@ -12,8 +12,6 @@
 set -e
 
 function init_flash_process() {
-  local method
-
   ### step 1: check for required userhgroups (tty & dialout)
   check_usergroups
 
@@ -29,6 +27,8 @@ function init_flash_process() {
   echo -e "| 2) Updating via SD-Card Update                        |"
   blank_line
   back_help_footer
+
+  local choice method
   while true; do
     read -p "${cyan}###### Please select:${white} " choice
     case "${choice}" in
@@ -54,6 +54,7 @@ function init_flash_process() {
 
   ### step 2: select how the mcu is connected to the host
   select_mcu_connection
+
   ### step 3: select which detected mcu should be flashed
   select_mcu_id "${method}"
 }
@@ -71,12 +72,11 @@ function select_mcu_connection() {
   echo -e "| 2) UART                                               |"
   blank_line
   back_help_footer
+
+  local choice
   while true; do
     read -p "${cyan}###### Connection method:${white} " choice
     case "${choice}" in
-      ### continue to execute script even if get_usb_id or get_uart_id returns with exit code 1
-      ### this is not critical, as the mcu_list array will be empty and that specific
-      ### case is handled later during execution of the script
       1)
         status_msg "Identifying MCU connected via USB ...\n"
         get_usb_id || true # continue even after exit code 1
@@ -101,7 +101,7 @@ function select_mcu_connection() {
 function print_detected_mcu_to_screen() {
   local i=1
 
-  if [ "${#mcu_list[@]}" -lt 1 ]; then
+  if (( ${#mcu_list[@]} < 1 )); then
     print_error "No MCU found!\n MCU eihter not connected or not detected!"
     return
   fi
@@ -109,7 +109,7 @@ function print_detected_mcu_to_screen() {
   for mcu in "${mcu_list[@]}"; do
     mcu=$(echo "${mcu}" | rev | cut -d"/" -f1 | rev)
     echo -e " ● MCU #${i}: ${cyan}${mcu}${white}"
-    i=$((i+1))
+    i=$(( i + 1 ))
   done
   echo
 }
@@ -120,7 +120,7 @@ function print_detected_mcu_to_screen() {
 function select_mcu_id() {
   local i=0 sel_index=0 method=${1}
 
-  if [ "${#mcu_list[@]}" -lt 1 ]; then
+  if (( ${#mcu_list[@]} < 1 )); then
     print_error "No MCU found!\n MCU eihter not connected or not detected!"
     return
   fi
@@ -132,25 +132,32 @@ function select_mcu_id() {
   echo -e "| ${red}ONLY flash a firmware created for the respective MCU!${white} |"
   bottom_border
   echo -e "${cyan}###### List of available MCU:${white}"
+
   ### list all mcus
   for mcu in "${mcu_list[@]}"; do
-    i=$((i+1))
+    i=$(( i + 1 ))
     mcu=$(echo "${mcu}" | rev | cut -d"/" -f1 | rev)
     echo -e " ● MCU #${i}: ${cyan}${mcu}${white}"
   done
+
   ### verify user input
-  while [[ ! (${sel_index} =~ ^[1-9]+$) ]] || [ "${sel_index}" -gt "${i}" ]; do
+  local regex="^[1-9]+$"
+  while [[ ! ${sel_index} =~ ${regex} ]] || [[ ${sel_index} -gt ${i} ]]; do
     echo
     read -p "${cyan}###### Select MCU to flash:${white} " sel_index
-    if [[ ! (${sel_index} =~ ^[1-9]+$) ]]; then
+
+    if [[ ! ${sel_index} =~ ${regex} ]]; then
       error_msg "Invalid input!"
-    elif [ "${sel_index}" -lt 1 ] || [ "${sel_index}" -gt "${i}" ]; then
+    elif [[ ${sel_index} -lt 1 ]] || [[ ${sel_index} -gt ${i} ]]; then
       error_msg "Please select a number between 1 and ${i}!"
     fi
-    mcu_index=$((sel_index - 1))
-    selected_mcu_id="${mcu_list[${mcu_index}]}"
+
+    local mcu_index=$(( sel_index - 1 ))
+    local selected_mcu_id="${mcu_list[${mcu_index}]}"
   done
+
   ### confirm selection
+  local yn
   while true; do
     echo -e "\n###### You selected:\n ● MCU #${sel_index}: ${selected_mcu_id}\n"
     read -p "${cyan}###### Continue? (Y/n):${white} " yn
@@ -158,10 +165,10 @@ function select_mcu_id() {
       Y|y|Yes|yes|"")
         select_msg "Yes"
         status_msg "Flashing ${selected_mcu_id} ..."
-        if [ "${method}" == "regular" ]; then
+        if [[ ${method} == "regular" ]]; then
           log_info "Flashing device '${selected_mcu_id}' with method '${method}'"
           start_flash_mcu "${selected_mcu_id}"
-        elif [ "${method}" == "sdcard" ]; then
+        elif [[ ${method} == "sdcard" ]]; then
           log_info "Flashing device '${selected_mcu_id}' with method '${method}'"
           start_flash_sd "${selected_mcu_id}"
         else
@@ -182,12 +189,14 @@ function select_mcu_id() {
 function start_flash_mcu() {
   local device=${1}
   do_action_service "stop" "klipper"
+
   if make flash FLASH_DEVICE="${device}"; then
     ok_msg "Flashing successfull!"
   else
     warn_msg "Flashing failed!"
     warn_msg "Please read the console output above!"
   fi
+
   do_action_service "start" "klipper"
 }
 
@@ -208,7 +217,7 @@ function start_flash_sd() {
   hr
   ### display all supported boards to the user
   for board in "${board_list[@]}"; do
-    if [ "${i}" -lt 10 ]; then
+    if [[ ${i} -lt 10 ]]; then
       printf "|  ${i}) %-50s|\n" "${board_list[${i}]}"
     else
       printf "|  ${i}) %-49s|\n" "${board_list[${i}]}"
@@ -218,11 +227,12 @@ function start_flash_sd() {
   quit_footer
 
   ### make the user select one of the boards
+  local choice
   while true; do
     read -p "${cyan}###### Please select board type:${white} " choice
-    if [ "${choice}" = "q" ] || [ "${choice}" = "Q" ]; then
+    if [[ ${choice} = "q" || ${choice} = "Q" ]]; then
       clear && advanced_menu && break
-    elif [ "${choice}" -le ${#board_list[@]} ]; then
+    elif [[ ${choice} -le ${#board_list[@]} ]]; then
       local selected_board="${board_list[${choice}]}"
       break
     else
@@ -240,8 +250,10 @@ function start_flash_sd() {
     blank_line
     echo -e "| If you are unsure, stick to the default 250000!       |"
     bottom_border
+
+    local baud_rate regex="^[0-9]+$"
     echo -e "${cyan}###### Please set the baud rate:${white} "
-    while [[ ! ${baud_rate} =~ ^[0-9]+$ ]]; do
+    while [[ ! ${baud_rate} =~ ${regex} ]]; do
       read -e -i "250000" -e baud_rate
       local selected_baud_rate=${baud_rate}
       break
@@ -301,6 +313,7 @@ function get_usb_id() {
   unset mcu_list
   sleep 1
   mcus=$(find /dev/serial/by-id/* 2>/dev/null)
+
   for mcu in ${mcus}; do
     mcu_list+=("${mcu}")
   done
@@ -310,6 +323,7 @@ function get_uart_id() {
   unset mcu_list
   sleep 1
   mcus=$(find /dev -maxdepth 1 -regextype posix-extended -regex "^\/dev\/tty[^0-9]+([0-9]+)?$" 2>/dev/null)
+
   for mcu in ${mcus}; do
     mcu_list+=("${mcu}")
   done
@@ -343,6 +357,8 @@ function show_flash_method_help() {
   echo -e "| - Fysetc Spider                                       |"
   blank_line
   back_footer
+
+  local choice
   while true; do
     read -p "${cyan}###### Please select:${white} " choice
     case "${choice}" in
@@ -377,6 +393,8 @@ function show_mcu_connection_help() {
   echo -e "| this connection method.                               |"
   blank_line
   back_footer
+
+  local choice
   while true; do
     read -p "${cyan}###### Please select:${white} " choice
     case "${choice}" in
diff --git a/scripts/fluidd.sh b/scripts/fluidd.sh
index 0ac8472..c6b173d 100644
--- a/scripts/fluidd.sh
+++ b/scripts/fluidd.sh
@@ -262,7 +262,7 @@ function get_fluidd_status() {
 
   if (( filecount == ${#data_arr[*]} )); then
     status="Installed!"
-  elif ((filecount == 0)); then
+  elif (( filecount == 0 )); then
     status="Not installed!"
   else
     status="Incomplete!"
diff --git a/scripts/gcode_shell_command.sh b/scripts/gcode_shell_command.sh
index 6fa57cb..7eae414 100644
--- a/scripts/gcode_shell_command.sh
+++ b/scripts/gcode_shell_command.sh
@@ -17,28 +17,33 @@ set -e
 
 function setup_gcode_shell_command() {
   top_border
-  echo -e "| You are about to install the G-Code Shell Command     |"
+  echo -e "| You are about to install the 'G-Code Shell Command'   |"
   echo -e "| extension. Please make sure to read the instructions  |"
   echo -e "| before you continue and remember that potential risks |"
   echo -e "| can be involved after installing this extension!      |"
   blank_line
   echo -e "| ${red}You accept that you are doing this on your own risk!${white}  |"
   bottom_border
+
+  local yn
   while true; do
     read -p "${cyan}###### Do you want to continue? (Y/n):${white} " yn
     case "${yn}" in
       Y|y|Yes|yes|"")
         select_msg "Yes"
-        if [ ! -d "${KLIPPER_DIR}/klippy/extras" ]; then
+
+        if [[ ! -d "${KLIPPER_DIR}/klippy/extras" ]]; then
           print_error "Folder ~/klipper/klippy/extras not found!\n      Klipper not installed yet?"
           return
         fi
 
         status_msg "Installing gcode shell command extension ..."
-        if [ ! -f "${KLIPPER_DIR}/klippy/extras/gcode_shell_command.py" ]; then
+
+        if [[ ! -f "${KLIPPER_DIR}/klippy/extras/gcode_shell_command.py" ]]; then
           install_gcode_shell_command
         else
           echo; warn_msg "File 'gcode_shell_command.py' already exists in the destination location!"
+
           while true; do
             read -p "${cyan}###### Do you want to overwrite it? (Y/n):${white} " yn
             case "${yn}" in
@@ -68,12 +73,15 @@ function setup_gcode_shell_command() {
 function install_gcode_shell_command() {
   do_action_service "stop" "klipper"
   status_msg "Copy 'gcode_shell_command.py' to '${KLIPPER_DIR}/klippy/extras' ..."
+
   if cp "${KIAUH_SRCDIR}/resources/gcode_shell_command.py" "${KLIPPER_DIR}/klippy/extras"; then
     ok_msg "Done!"
   else
     error_msg "Cannot copy file to target destination...Exiting!"
     return 1
   fi
+
+  local yn
   while true; do
     echo
     read -p "${cyan}###### Create an example shell command? (Y/n):${white} " yn
@@ -87,6 +95,7 @@ function install_gcode_shell_command() {
         break;;
     esac
   done
+
   do_action_service "restart" "klipper"
   print_confirm "Shell command extension installed!"
   return
@@ -96,15 +105,17 @@ function create_example_shell_command() {
   ### create a backup of the config folder
   backup_klipper_config_dir
 
-  local printer_cfgs
+  local printer_cfgs path
   printer_cfgs=$(find "$(get_klipper_cfg_dir)" -type f -name "printer.cfg" | sort)
+
   for cfg in ${printer_cfgs}; do
     path=$(echo "${cfg}" | rev | cut -d"/" -f2- | rev)
-    if [ ! -f "${path}/shell_command.cfg" ]; then
+
+    if [[ ! -f "${path}/shell_command.cfg" ]]; then
       status_msg "Copy shell_command.cfg to ${path} ..."
       cp "${KIAUH_SRCDIR}/resources/shell_command.cfg" "${path}"
       ok_msg "${path}/shell_command.cfg created!"
-      ### write the include to the very first line of the printer.cfg
+      ### write include to the very first line of the printer.cfg
       sed -i "1 i [include shell_command.cfg]" "${cfg}"
     fi
   done
diff --git a/scripts/klipper.sh b/scripts/klipper.sh
index 82218a7..e802ade 100644
--- a/scripts/klipper.sh
+++ b/scripts/klipper.sh
@@ -492,7 +492,7 @@ function get_klipper_status() {
 
   ### remove the "SERVICE" entry from the data array if a klipper service is installed
   local data_arr=(SERVICE "${KLIPPER_DIR}" "${KLIPPY_ENV}")
-  [[ ${sf_count} -gt 0 ]] && unset "data_arr[0]"
+  (( sf_count > 0 )) && unset "data_arr[0]"
 
   ### count+1 for each found data-item from array
   local filecount=0
diff --git a/scripts/klipperscreen.sh b/scripts/klipperscreen.sh
index 5d0f211..f05f3ea 100644
--- a/scripts/klipperscreen.sh
+++ b/scripts/klipperscreen.sh
@@ -23,7 +23,7 @@ function klipperscreen_systemd() {
 
 function install_klipperscreen() {
   ### return early if python version check fails
-  if [ "$(python3_check)" == "false" ]; then
+  if [[ $(python3_check) == "false" ]]; then
     local error="Versioncheck failed! Python 3.7 or newer required!\n"
     error="${error} Please upgrade Python."
     print_error "${error}" && return
@@ -42,8 +42,10 @@ function klipperscreen_setup() {
   local dep=(wget curl unzip dfu-util)
   dependency_check "${dep[@]}"
   status_msg "Downloading KlipperScreen ..."
+
   # force remove existing KlipperScreen dir
-  [ -d "${KLIPPERSCREEN_DIR}" ] && rm -rf "${KLIPPERSCREEN_DIR}"
+  [[ -d ${KLIPPERSCREEN_DIR} ]] && rm -rf "${KLIPPERSCREEN_DIR}"
+
   # clone into fresh KlipperScreen dir
   cd "${HOME}" && git clone "${KLIPPERSCREEN_REPO}"
   ok_msg "Download complete!"
@@ -58,23 +60,24 @@ function klipperscreen_setup() {
 
 function remove_klipperscreen() {
   ### remove KlipperScreen dir
-  if [ -d "${KLIPPERSCREEN_DIR}" ]; then
+  if [[ -d ${KLIPPERSCREEN_DIR} ]]; then
     status_msg "Removing KlipperScreen directory ..."
     rm -rf "${KLIPPERSCREEN_DIR}" && ok_msg "Directory removed!"
   fi
 
   ### remove KlipperScreen VENV dir
-  if [ -d "${KLIPPERSCREEN_ENV}" ]; then
+  if [[ -d ${KLIPPERSCREEN_ENV} ]]; then
     status_msg "Removing KlipperScreen VENV directory ..."
     rm -rf "${KLIPPERSCREEN_ENV}" && ok_msg "Directory removed!"
   fi
 
   ### remove KlipperScreen service
-  if [ -e "${SYSTEMD}/KlipperScreen.service" ]; then
+  if [[ -e "${SYSTEMD}/KlipperScreen.service" ]]; then
     status_msg "Removing KlipperScreen service ..."
     do_action_service "stop" "KlipperScreen"
     do_action_service "disable" "KlipperScreen"
     sudo rm -f "${SYSTEMD}/KlipperScreen.service"
+
     ###reloading units
     sudo systemctl daemon-reload
     sudo systemctl reset-failed
@@ -82,14 +85,13 @@ function remove_klipperscreen() {
   fi
 
   ### remove KlipperScreen log
-  if [ -e "/tmp/KlipperScreen.log" ]; then
+  if [[ -e "/tmp/KlipperScreen.log" ]]; then
     status_msg "Removing KlipperScreen log file ..."
     rm -f "/tmp/KlipperScreen.log" && ok_msg "File removed!"
   fi
 
   ### remove KlipperScreen log symlink in config dir
-
-  if [ -e "${KLIPPER_CONFIG}/KlipperScreen.log" ]; then
+  if [[ -e "${KLIPPER_CONFIG}/KlipperScreen.log" ]]; then
     status_msg "Removing KlipperScreen log symlink ..."
     rm -f "${KLIPPER_CONFIG}/KlipperScreen.log" && ok_msg "File removed!"
   fi
@@ -109,11 +111,13 @@ function update_klipperscreen() {
   cd "${KLIPPERSCREEN_DIR}"
   git pull origin master -q && ok_msg "Fetch successfull!"
   git checkout -f master && ok_msg "Checkout successfull"
+
   if [[ $(md5sum "${KLIPPERSCREEN_DIR}/scripts/KlipperScreen-requirements.txt" | cut -d " " -f1) != "${old_md5}" ]]; then
     status_msg "New dependecies detected..."
     "${KLIPPERSCREEN_ENV}"/bin/pip install -r "${KLIPPERSCREEN_DIR}/scripts/KlipperScreen-requirements.txt"
     ok_msg "Dependencies have been installed!"
   fi
+
   ok_msg "Update complete!"
   do_action_service "start" "KlipperScreen"
 }
@@ -128,17 +132,17 @@ function get_klipperscreen_status() {
 
   ### remove the "SERVICE" entry from the data array if a moonraker service is installed
   local data_arr=(SERVICE "${KLIPPERSCREEN_DIR}" "${KLIPPERSCREEN_ENV}")
-  [ "${sf_count}" -gt 0 ] && unset "data_arr[0]"
+  (( sf_count > 0)) && unset "data_arr[0]"
 
   ### count+1 for each found data-item from array
   local filecount=0
   for data in "${data_arr[@]}"; do
-    [ -e "${data}" ] && filecount=$(("${filecount}" + 1))
+    [[ -e ${data} ]] && filecount=$(( filecount + 1 ))
   done
 
-  if (( filecount == ${#data_arr[*]})); then
+  if (( filecount == ${#data_arr[*]} )); then
     status="Installed!"
-  elif ((filecount == 0)); then
+  elif (( filecount == 0 )); then
     status="Not installed!"
   else
     status="Incomplete!"
@@ -147,16 +151,18 @@ function get_klipperscreen_status() {
 }
 
 function get_local_klipperscreen_commit() {
+  [[ ! -d ${KLIPPERSCREEN_DIR} || ! -d "${KLIPPERSCREEN_DIR}/.git" ]] && return
+
   local commit
-  [ ! -d "${KLIPPERSCREEN_DIR}" ] || [ ! -d "${KLIPPERSCREEN_DIR}"/.git ] && return
   cd "${KLIPPERSCREEN_DIR}"
   commit="$(git describe HEAD --always --tags | cut -d "-" -f 1,2)"
   echo "${commit}"
 }
 
 function get_remote_klipperscreen_commit() {
+  [[ ! -d ${KLIPPERSCREEN_DIR} || ! -d "${KLIPPERSCREEN_DIR}/.git" ]] && return
+
   local commit
-  [ ! -d "${KLIPPERSCREEN_DIR}" ] || [ ! -d "${KLIPPERSCREEN_DIR}"/.git ] && return
   cd "${KLIPPERSCREEN_DIR}" && git fetch origin -q
   commit=$(git describe origin/master --always --tags | cut -d "-" -f 1,2)
   echo "${commit}"
@@ -167,7 +173,8 @@ function compare_klipperscreen_versions() {
   local versions local_ver remote_ver
   local_ver="$(get_local_klipperscreen_commit)"
   remote_ver="$(get_remote_klipperscreen_commit)"
-  if [ "${local_ver}" != "${remote_ver}" ]; then
+
+  if [[ ${local_ver} != "${remote_ver}" ]]; then
     versions="${yellow}$(printf " %-14s" "${local_ver}")${white}"
     versions+="|${green}$(printf " %-13s" "${remote_ver}")${white}"
     # add klipperscreen to the update all array for the update all function in the updater
@@ -177,6 +184,7 @@ function compare_klipperscreen_versions() {
     versions+="|${green}$(printf " %-13s" "${remote_ver}")${white}"
     KLIPPERSCREEN_UPDATE_AVAIL="false"
   fi
+
   echo "${versions}"
 }
 
@@ -187,10 +195,12 @@ function compare_klipperscreen_versions() {
 function patch_klipperscreen_update_manager() {
   local moonraker_configs
   moonraker_configs=$(find "$(get_klipper_cfg_dir)" -type f -name "moonraker.conf" | sort)
+
   for conf in ${moonraker_configs}; do
     if ! grep -Eq "[update_manager KlipperScreen]" "${conf}"; then
       ### add new line to conf if it doesn't end with one
       [[ $(tail -c1 "${conf}" | wc -l) -eq 0 ]] && echo "" >> "${conf}"
+
       ### add KlipperScreens update manager section to moonraker.conf
       status_msg "Adding KlipperScreen to update manager in file:\n       ${conf}"
       /bin/sh -c "cat >> ${conf}" << MOONRAKER_CONF
@@ -203,6 +213,7 @@ env: ${HOME}/.KlipperScreen-env/bin/python
 requirements: scripts/KlipperScreen-requirements.txt
 install_script: scripts/KlipperScreen-install.sh
 MOONRAKER_CONF
+
     fi
   done
 }
diff --git a/scripts/mainsail.sh b/scripts/mainsail.sh
index 9fe3ea3..9ad261b 100644
--- a/scripts/mainsail.sh
+++ b/scripts/mainsail.sh
@@ -322,7 +322,7 @@ function print_theme_list() {
     if [[ ${col1} != "name" ]]; then
       printf "|  ${i}) %-50s|\n" "[${col1}]"
     fi
-    i=$((i+1))
+    i=$(( i + 1 ))
   done <<< "${theme_list}"
 }
 
diff --git a/scripts/mjpg-streamer.sh b/scripts/mjpg-streamer.sh
index 95f508c..9358b06 100644
--- a/scripts/mjpg-streamer.sh
+++ b/scripts/mjpg-streamer.sh
@@ -22,7 +22,7 @@ function install_mjpg-streamer() {
   local service="${KIAUH_SRCDIR}/resources/webcamd.service"
 
   ### return early if webcamd.service already exists
-  if [ -f "${SYSTEMD}/webcamd.service" ]; then
+  if [[ -f "${SYSTEMD}/webcamd.service" ]]; then
     print_error "Looks like MJPG-streamer is already installed!\n Please remove it first before you try to re-install it!"
     return
   fi
@@ -36,11 +36,12 @@ function install_mjpg-streamer() {
   elif apt-cache search libjpeg8-dev | grep -Eq "^libjpeg8-dev "; then
     dep+=(libjpeg8-dev)
   fi
+
   dependency_check "${dep[@]}"
 
   ### step 1: clone mjpg-streamer
   status_msg "Downloading MJPG-Streamer ..."
-  [ -d "${HOME}/mjpg-streamer" ] && rm -rf "${HOME}/mjpg-streamer"
+  [[ -d "${HOME}/mjpg-streamer" ]] && rm -rf "${HOME}/mjpg-streamer"
   cd "${HOME}" && git clone "${repo}"
   ok_msg "Download complete!"
 
@@ -53,6 +54,7 @@ function install_mjpg-streamer() {
   status_msg "Installing MJPG-Streamer ..."
   cd "${HOME}/mjpg-streamer" && mv mjpg-streamer-experimental/* .
   mkdir www-mjpgstreamer
+
   cat <<EOT >> ./www-mjpgstreamer/index.html
 <html>
 <head><title>mjpg_streamer test page</title></head>
@@ -65,14 +67,15 @@ function install_mjpg-streamer() {
 </body>
 </html>
 EOT
+
   sudo wget "${webcamd}" -O "/usr/local/bin/webcamd"
   sudo sed -i "/^config_dir=/ s|=.*|=${KLIPPER_CONFIG}|" /usr/local/bin/webcamd
   sudo sed -i "/MJPGSTREAMER_HOME/ s/pi/${USER}/" /usr/local/bin/webcamd
   sudo chmod +x /usr/local/bin/webcamd
 
   ### step 4: create webcam.txt config file
-  [ ! -d "${KLIPPER_CONFIG}" ] && mkdir -p "${KLIPPER_CONFIG}"
-  if [ ! -f "${KLIPPER_CONFIG}/webcam.txt" ]; then
+  [[ ! -d ${KLIPPER_CONFIG} ]] && mkdir -p "${KLIPPER_CONFIG}"
+  if [[ ! -f "${KLIPPER_CONFIG}/webcam.txt" ]]; then
     status_msg "Creating webcam.txt config file ..."
     wget "${webcam_txt}" -O "${KLIPPER_CONFIG}/webcam.txt"
     ok_msg "Done!"
@@ -94,13 +97,13 @@ EOT
   fi
 
   ### step 6.1: create webcamd.log symlink
-  [ ! -d "${KLIPPER_LOGS}" ] && mkdir -p "${KLIPPER_LOGS}"
-  if [ -f "/var/log/webcamd.log" ] && [ ! -L "${KLIPPER_LOGS}/webcamd.log" ]; then
+  [[ ! -d ${KLIPPER_LOGS} ]] && mkdir -p "${KLIPPER_LOGS}"
+  if [[ -f "/var/log/webcamd.log" && ! -L "${KLIPPER_LOGS}/webcamd.log" ]]; then
     ln -s "/var/log/webcamd.log" "${KLIPPER_LOGS}/webcamd.log"
   fi
 
   ### step 6.2: add webcamd.log logrotate
-  if [ ! -f "/etc/logrotate.d/webcamd"  ]; then
+  if [[ ! -f "/etc/logrotate.d/webcamd"  ]]; then
     status_msg "Create logrotate rule ..."
     sudo /bin/sh -c "cat > /etc/logrotate.d/webcamd" << EOF
 /var/log/webcamd.log
@@ -121,7 +124,8 @@ EOF
   ### step 7: check if user is in group "video"
   local usergroup_changed="false" usergroup_video
   usergroup_video=$(groups "${USER}" | grep "video")
-  if [ -z "${usergroup_video}" ]; then
+
+  if [[ -z ${usergroup_video} ]]; then
     status_msg "Adding user ${USER} to group 'video' ..."
     sudo usermod -a -G video "${USER}" && ok_msg "Done!"
     usergroup_changed="true"
@@ -129,10 +133,11 @@ EOF
 
   ### confirm message
   local confirm_msg="MJPG-Streamer has been set up!"
-  if [ "${usergroup_changed}" == "true" ]; then
+  if [[ ${usergroup_changed} == "true" ]]; then
     confirm_msg="${confirm_msg}\n ${yellow}INFO: Your User was added to a new group!${green}"
     confirm_msg="${confirm_msg}\n ${yellow}You need to relog/restart for the group to be applied!${green}"
   fi
+
   print_confirm "${confirm_msg}"
 
   ### print webcam ip adress/url
@@ -151,7 +156,7 @@ EOF
 
 function remove_mjpg-streamer() {
   ### remove MJPG-Streamer service
-  if [ -e "${SYSTEMD}/webcamd.service" ]; then
+  if [[ -e "${SYSTEMD}/webcamd.service" ]]; then
     status_msg "Removing MJPG-Streamer service ..."
     sudo systemctl stop webcamd && sudo systemctl disable webcamd
     sudo rm -f "${SYSTEMD}/webcamd.service"
@@ -162,20 +167,20 @@ function remove_mjpg-streamer() {
   fi
 
   ### remove webcamd from /usr/local/bin
-  if [ -e "/usr/local/bin/webcamd" ]; then
+  if [[ -e "/usr/local/bin/webcamd" ]]; then
     sudo rm -f "/usr/local/bin/webcamd"
   fi
 
   ### remove MJPG-Streamer directory
-  if [ -d "${HOME}/mjpg-streamer" ]; then
+  if [[ -d "${HOME}/mjpg-streamer" ]]; then
     status_msg "Removing MJPG-Streamer directory ..."
     rm -rf "${HOME}/mjpg-streamer"
     ok_msg "MJPG-Streamer directory removed!"
   fi
 
   ### remove webcamd log and symlink
-  [ -f "/var/log/webcamd.log" ] && sudo rm -f "/var/log/webcamd.log"
-  [ -L "${KLIPPER_LOGS}/webcamd.log" ] && rm -f "${KLIPPER_LOGS}/webcamd.log"
+  [[ -f "/var/log/webcamd.log" ]] && sudo rm -f "/var/log/webcamd.log"
+  [[ -L "${KLIPPER_LOGS}/webcamd.log" ]] && rm -f "${KLIPPER_LOGS}/webcamd.log"
 
   print_confirm "MJPG-Streamer successfully removed!"
 }
\ No newline at end of file
diff --git a/scripts/moonraker.sh b/scripts/moonraker.sh
index 0e2ec5f..c62f8bc 100644
--- a/scripts/moonraker.sh
+++ b/scripts/moonraker.sh
@@ -504,7 +504,7 @@ function get_moonraker_status() {
 
   ### remove the "SERVICE" entry from the data array if a moonraker service is installed
   local data_arr=(SERVICE "${MOONRAKER_DIR}" "${MOONRAKER_ENV}")
-  [[ ${sf_count} -gt 0 ]] && unset "data_arr[0]"
+  (( sf_count > 0 )) && unset "data_arr[0]"
 
   ### count+1 for each found data-item from array
   local filecount=0
diff --git a/scripts/nginx.sh b/scripts/nginx.sh
index bf8f62c..932a05c 100644
--- a/scripts/nginx.sh
+++ b/scripts/nginx.sh
@@ -16,13 +16,15 @@ set -e
 #===================================================#
 
 function remove_nginx() {
-  if [ -f "${SYSTEMD}/nginx.service" ]; then
+  if [[ -f "${SYSTEMD}/nginx.service" ]]; then
     status_msg "Stopping Nginx service ..."
     sudo systemctl stop nginx && sudo systemctl disable nginx
     ok_msg "Service stopped and disabled!"
+
     status_msg "Purging Nginx from system ..."
     sudo apt-get purge nginx nginx-common -y
     sudo update-rc.d -f nginx remove
+
     print_confirm "Nginx successfully removed!"
   else
     print_error "Looks like Nginx was already removed!\n Skipping..."
@@ -35,42 +37,52 @@ function remove_nginx() {
 
 function set_upstream_nginx_cfg() {
   local current_date
-  current_date=$(get_date)
   local upstreams="${NGINX_CONFD}/upstreams.conf"
   local common_vars="${NGINX_CONFD}/common_vars.conf"
+
+  current_date=$(get_date)
+
   ### backup existing nginx configs
-  [ ! -d "${BACKUP_DIR}/nginx_cfg" ] && mkdir -p "${BACKUP_DIR}/nginx_cfg"
-  if [ -f "${upstreams}" ]; then
+  [[ ! -d "${BACKUP_DIR}/nginx_cfg" ]] && mkdir -p "${BACKUP_DIR}/nginx_cfg"
+
+  if [[ -f ${upstreams} ]]; then
     sudo mv "${upstreams}" "${BACKUP_DIR}/nginx_cfg/${current_date}_upstreams.conf"
   fi
-  if [ -f "${common_vars}" ]; then
+
+  if [[ -f ${common_vars} ]]; then
     sudo mv "${common_vars}" "${BACKUP_DIR}/nginx_cfg/${current_date}_common_vars.conf"
   fi
+
   ### transfer ownership of backed up files from root to ${USER}
   local files
   files=$(find "${BACKUP_DIR}/nginx_cfg")
+
   for file in ${files}; do
-    if [ "$(stat -c "%U" "${file}" )" != "${USER}" ]; then
+    if [[ $(stat -c "%U" "${file}") != "${USER}" ]]; then
       log_info "chown for user: ${USER} on file: ${file}"
       sudo chown "${USER}" "${file}"
     fi
   done
+
   ### copy nginx configs to target destination
-  [ ! -f "${upstreams}" ] && sudo cp "${RESOURCES}/upstreams.conf" "${upstreams}"
-  [ ! -f "${common_vars}" ] && sudo cp "${RESOURCES}/common_vars.conf" "${common_vars}"
+  [[ ! -f ${upstreams} ]] && sudo cp "${RESOURCES}/upstreams.conf" "${upstreams}"
+  [[ ! -f ${common_vars} ]] && sudo cp "${RESOURCES}/common_vars.conf" "${common_vars}"
 }
 
 function symlink_webui_nginx_log() {
   local interface=${1} path="${KLIPPER_LOGS}"
   local access_log="/var/log/nginx/${interface}-access.log"
   local error_log="/var/log/nginx/${interface}-error.log"
-  [ ! -d "${path}" ] && mkdir -p "${path}"
-  if [ -f "${access_log}" ] &&  [ ! -L "${path}/${interface}-access.log" ]; then
+
+  [[ ! -d ${path} ]] && mkdir -p "${path}"
+
+  if [[ -f ${access_log} && ! -L "${path}/${interface}-access.log" ]]; then
     status_msg "Creating symlink for ${access_log} ..."
     ln -s "${access_log}" "${path}"
     ok_msg "Done!"
   fi
-  if [ -f "${error_log}" ] &&  [ ! -L "${path}/${interface}-error.log" ]; then
+
+  if [[ -f ${error_log} && ! -L "${path}/${interface}-error.log" ]]; then
     status_msg "Creating symlink for ${error_log} ..."
     ln -s "${error_log}" "${path}"
     ok_msg "Done!"
@@ -90,58 +102,69 @@ function match_nginx_configs() {
   upstreams_webcams=$(grep -Ec "mjpgstreamer" "/etc/nginx/conf.d/upstreams.conf")
   mainsail_webcams=$(grep -Ec "mjpgstreamer" "${mainsail_nginx_cfg}" 2>/dev/null || echo "0")
   fluidd_webcams=$(grep -Ec "mjpgstreamer" "${fluidd_nginx_cfg}" 2>/dev/null || echo "0")
+
   status_msg "Checking validity of NGINX configurations ..."
+
   ### check for outdated upstreams.conf
-  if ((upstreams_webcams < mainsail_webcams || upstreams_webcams < fluidd_webcams)); then
+  if (( upstreams_webcams < mainsail_webcams || upstreams_webcams < fluidd_webcams )); then
     status_msg "Outdated upstreams.conf found! Updating ..."
+
     sudo rm -f "${upstreams}" "${common_vars}"
     set_upstream_nginx_cfg
+
     require_service_restart="true"
     ok_msg "Done!"
   fi
+
   ### check for outdated mainsail config
-  if [ -e "${mainsail_nginx_cfg}" ] && ((upstreams_webcams > mainsail_webcams)); then
+  if [[ -e ${mainsail_nginx_cfg} ]] && (( upstreams_webcams > mainsail_webcams )); then
     status_msg "Outdated Mainsail config found! Updating ..."
+
     sudo rm -f "${mainsail_nginx_cfg}"
     sudo cp "${RESOURCES}/klipper_webui_nginx.cfg" "${mainsail_nginx_cfg}"
     sudo sed -i "s/<<UI>>/mainsail/g" "${mainsail_nginx_cfg}"
     sudo sed -i "/root/s/pi/${USER}/" "${mainsail_nginx_cfg}"
     sudo sed -i "s/listen\s[0-9]*;/listen ${mainsail_port};/" "${mainsail_nginx_cfg}"
     sudo sed -i "s/listen\s\[\:*\]\:[0-9]*;/listen \[::\]\:${mainsail_port};/" "${mainsail_nginx_cfg}"
+
     require_service_restart="true"
     ok_msg "Done!"
   fi
+
   ### check for outdated fluidd config
-  if [ -e "${fluidd_nginx_cfg}" ] && ((upstreams_webcams > fluidd_webcams)); then
+  if [[ -e ${fluidd_nginx_cfg} ]] && (( upstreams_webcams > fluidd_webcams )); then
     status_msg "Outdated Fluidd config found! Updating ..."
+
     sudo rm -f "${fluidd_nginx_cfg}"
     sudo cp "${RESOURCES}/klipper_webui_nginx.cfg" "${fluidd_nginx_cfg}"
     sudo sed -i "s/<<UI>>/fluidd/g" "${fluidd_nginx_cfg}"
     sudo sed -i "/root/s/pi/${USER}/" "${fluidd_nginx_cfg}"
     sudo sed -i "s/listen\s[0-9]*;/listen ${fluidd_port};/" "${fluidd_nginx_cfg}"
     sudo sed -i "s/listen\s\[\:*\]\:[0-9]*;/listen \[::\]\:${fluidd_port};/" "${fluidd_nginx_cfg}"
+
     require_service_restart="true"
     ok_msg "Done!"
   fi
+
   ### only restart nginx if configs were updated
-  [ "${require_service_restart}" == "true" ] && sudo systemctl restart nginx.service
+  [[ ${require_service_restart} == "true" ]] && sudo systemctl restart nginx.service
 }
 
 function process_disruptive_services() {
   #handle haproxy service
-  if [ "${DISABLE_HAPROXY}" = "true" ] || [ "${REMOVE_HAPROXY}" = "true" ]; then
+  if [[ ${DISABLE_HAPROXY} == "true" || ${REMOVE_HAPROXY} == "true" ]]; then
     if systemctl is-active haproxy -q; then
       status_msg "Stopping haproxy service ..."
       sudo systemctl stop haproxy && ok_msg "Service stopped!"
     fi
 
     ### disable haproxy
-    if [ "${DISABLE_HAPROXY}" = "true" ]; then
+    if [[ ${DISABLE_HAPROXY} == "true" ]]; then
       status_msg "Disabling haproxy ..."
       sudo systemctl disable haproxy && ok_msg "Haproxy service disabled!"
 
       ### remove haproxy
-      if [ "${REMOVE_HAPROXY}" = "true" ]; then
+      if [[ ${REMOVE_HAPROXY} == "true" ]]; then
         status_msg "Removing haproxy ..."
         sudo apt-get remove haproxy -y && sudo update-rc.d -f haproxy remove && ok_msg "Haproxy removed!"
       fi
@@ -149,19 +172,19 @@ function process_disruptive_services() {
   fi
 
   ### handle lighttpd service
-  if [ "${DISABLE_LIGHTTPD}" = "true" ] || [ "${REMOVE_LIGHTTPD}" = "true" ]; then
+  if [[ ${DISABLE_LIGHTTPD} == "true" || ${REMOVE_LIGHTTPD} == "true" ]]; then
     if systemctl is-active lighttpd -q; then
       status_msg "Stopping lighttpd service ..."
       sudo systemctl stop lighttpd && ok_msg "Service stopped!"
     fi
 
     ### disable lighttpd
-    if [ "${DISABLE_LIGHTTPD}" = "true" ]; then
+    if [[ ${DISABLE_LIGHTTPD} == "true" ]]; then
       status_msg "Disabling lighttpd ..."
       sudo systemctl disable lighttpd && ok_msg "Lighttpd service disabled!"
 
       ### remove lighttpd
-      if [ "${REMOVE_LIGHTTPD}" = "true" ]; then
+      if [[ ${REMOVE_LIGHTTPD} == "true" ]]; then
         status_msg "Removing lighttpd ..."
         sudo apt-get remove lighttpd -y && sudo update-rc.d -f lighttpd remove && ok_msg "Lighttpd removed!"
       fi
@@ -169,19 +192,19 @@ function process_disruptive_services() {
   fi
 
   ### handle apache2 service
-  if [ "${DISABLE_APACHE2}" = "true" ] || [ "${REMOVE_APACHE2}" = "true" ]; then
+  if [[ ${DISABLE_APACHE2} == "true" || ${REMOVE_APACHE2} == "true" ]]; then
     if systemctl is-active apache2 -q; then
       status_msg "Stopping apache2 service ..."
       sudo systemctl stop apache2 && ok_msg "Service stopped!"
     fi
 
     ### disable lighttpd
-    if [ "${DISABLE_APACHE2}" = "true" ]; then
+    if [[ ${DISABLE_APACHE2} == "true" ]]; then
       status_msg "Disabling lighttpd ..."
       sudo systemctl disable apache2 && ok_msg "Apache2 service disabled!"
 
       ### remove lighttpd
-      if [ "${REMOVE_APACHE2}" = "true" ]; then
+      if [[ ${REMOVE_APACHE2} == "true" ]]; then
         status_msg "Removing apache2 ..."
         sudo apt-get remove apache2 -y && sudo update-rc.d -f apache2 remove && ok_msg "Apache2 removed!"
       fi
@@ -191,29 +214,31 @@ function process_disruptive_services() {
 
 function process_services_dialog() {
   #notify user about haproxy or lighttpd services found and possible issues
-  if [ "${HAPROXY_FOUND}" = "true" ] || [ "${LIGHTTPD_FOUND}" = "true" ] || [ "${APACHE2_FOUND}" = "true" ]; then
+  if [[ ${HAPROXY_FOUND} == "true" || ${LIGHTTPD_FOUND} == "true" || ${APACHE2_FOUND} == "true" ]]; then
     while true; do
       echo
       top_border
       echo -e "| ${red}Possibly disruptive/incompatible services found!${white}      |"
       hr
-      if [ "${HAPROXY_FOUND}" = "true" ]; then
+      if [[ ${HAPROXY_FOUND} == "true" ]]; then
         echo -e "| ● haproxy                                             |"
       fi
-      if [ "${LIGHTTPD_FOUND}" = "true" ]; then
+      if [[ ${LIGHTTPD_FOUND} == "true" ]]; then
         echo -e "| ● lighttpd                                            |"
       fi
-      if [ "${APACHE2_FOUND}" = "true" ]; then
+      if [[ ${APACHE2_FOUND} == "true" ]]; then
         echo -e "| ● apache2                                             |"
       fi
       hr
       echo -e "| Having those packages installed can lead to unwanted  |"
-      echo -e "| behaviour. It is recommend to remove those packages.  |"
+      echo -e "| behaviour. It's recommended to remove those packages. |"
       echo -e "|                                                       |"
       echo -e "| 1) Remove packages (recommend)                        |"
       echo -e "| 2) Disable only (may cause issues)                    |"
       echo -e "| ${red}3) Skip this step (not recommended)${white}                   |"
       bottom_border
+
+      local action
       read -p "${cyan}###### Please choose:${white} " action
       case "${action}" in
         1)
@@ -241,42 +266,43 @@ function process_services_dialog() {
 
 function set_nginx_cfg() {
   local interface=${1}
-  if [ "${SET_NGINX_CFG}" = "true" ]; then
+  if [[ ${SET_NGINX_CFG} == "true" ]]; then
     local cfg="${RESOURCES}/${interface}"
     #check for dependencies
     local dep=(nginx)
     dependency_check "${dep[@]}"
-    #execute operations
+
     status_msg "Creating Nginx configuration for ${interface^} ..."
-    #copy content from resources to the respective nginx config file
     cat "${RESOURCES}/klipper_webui_nginx.cfg" > "${cfg}"
-    ##edit the nginx config file before moving it
     sed -i "s/<<UI>>/${interface}/g" "${cfg}"
-    if [ "${SET_LISTEN_PORT}" != "${DEFAULT_PORT}" ]; then
+
+    if [[ ${SET_LISTEN_PORT} != "${DEFAULT_PORT}" ]]; then
       status_msg "Configuring port for ${interface^} ..."
-      #set listen port ipv4
       sed -i "s/listen\s[0-9]*;/listen ${SET_LISTEN_PORT};/" "${cfg}"
-      #set listen port ipv6
       sed -i "s/listen\s\[\:*\]\:[0-9]*;/listen \[::\]\:${SET_LISTEN_PORT};/" "${cfg}"
     fi
+
     #set correct user
-    if [ "${interface}" = "mainsail" ] || [ "${interface}" = "fluidd" ]; then
+    if [[ ${interface} == "mainsail" || ${interface} == "fluidd" ]]; then
       sudo sed -i "/root/s/pi/${USER}/" "${cfg}"
     fi
+
     #moving the config file into correct directory
     sudo mv "${cfg}" "/etc/nginx/sites-available/${interface}"
     ok_msg "Nginx configuration for ${interface^} was set!"
-    if [ -n "${SET_LISTEN_PORT}" ]; then
+    if [[ -n ${SET_LISTEN_PORT} ]]; then
       ok_msg "${interface^} configured for port ${SET_LISTEN_PORT}!"
     else
       ok_msg "${interface^} configured for default port ${DEFAULT_PORT}!"
     fi
+
     #remove nginx default config
-    if [ -e "/etc/nginx/sites-enabled/default" ]; then
+    if [[ -e "/etc/nginx/sites-enabled/default" ]]; then
       sudo rm "/etc/nginx/sites-enabled/default"
     fi
+
     #create symlink for own sites
-    if [ ! -e "/etc/nginx/sites-enabled/${interface}" ]; then
+    if [[ ! -e "/etc/nginx/sites-enabled/${interface}" ]]; then
       sudo ln -s "/etc/nginx/sites-available/${interface}" "/etc/nginx/sites-enabled/"
     fi
     sudo systemctl restart nginx.service
@@ -292,16 +318,16 @@ function read_listen_port() {
 function detect_enabled_sites() {
   MAINSAIL_ENABLED="false" FLUIDD_ENABLED="false" OCTOPRINT_ENABLED="false"
   #check if there is another UI config already installed and reads the port they are listening on
-  if [ -e "/etc/nginx/sites-enabled/mainsail" ]; then
+  if [[ -e "/etc/nginx/sites-enabled/mainsail" ]]; then
     SITE_ENABLED="true" && MAINSAIL_ENABLED="true"
     MAINSAIL_PORT=$(read_listen_port "mainsail")
   fi
-  if [ -e "/etc/nginx/sites-enabled/fluidd" ]; then
+  if [[ -e "/etc/nginx/sites-enabled/fluidd" ]]; then
     SITE_ENABLED="true" && FLUIDD_ENABLED="true"
     FLUIDD_PORT=$(read_listen_port "fluidd")
 
   fi
-  if [ -e "/etc/nginx/sites-enabled/octoprint" ]; then
+  if [[ -e "/etc/nginx/sites-enabled/octoprint" ]]; then
     SITE_ENABLED="true" && OCTOPRINT_ENABLED="true"
     OCTOPRINT_PORT=$(read_listen_port "octoprint")
   fi
diff --git a/scripts/octoprint.sh b/scripts/octoprint.sh
index 961b429..d5ef214 100644
--- a/scripts/octoprint.sh
+++ b/scripts/octoprint.sh
@@ -27,6 +27,7 @@ function octoprint_setup_dialog() {
   local klipper_services klipper_count user_input=() klipper_names=()
   klipper_services=$(klipper_systemd)
   klipper_count=$(echo "${klipper_services}" | wc -w )
+
   for service in ${klipper_services}; do
     klipper_names+=( "$(get_instance_name "${service}")" )
   done
@@ -35,6 +36,7 @@ function octoprint_setup_dialog() {
   if (( klipper_count == 1 )); then
     ok_msg "Klipper installation found!\n"
     octoprint_count=1
+
   elif (( klipper_count > 1 )); then
     top_border
     printf "|${green}%-55s${white}|\n" " ${klipper_count} Klipper instances found!"
@@ -59,6 +61,7 @@ function octoprint_setup_dialog() {
       [[ ! ${octoprint_count} =~ ${re} ]] && error_msg "Input not a number"
       (( octoprint_count > klipper_count )) && error_msg "Number of OctoPrint instances larger than existing Klipper instances"
     done && select_msg "${octoprint_count}"
+
   else
     log_error "Internal error. octoprint_count of '${octoprint_count}' not equal or grather than one!"
     return 1
@@ -308,12 +311,12 @@ function print_op_ip_list() {
 #=================================================#
 
 function remove_octoprint_service() {
-  [[ -z "$(octoprint_systemd)" ]] && return
+  [[ -z $(octoprint_systemd) ]] && return
 
   ###remove all octoprint services
   status_msg "Removing OctoPrint Systemd Services ..."
-  for service in $(octoprint_systemd | cut -d"/" -f5)
-  do
+
+  for service in $(octoprint_systemd | cut -d"/" -f5); do
     status_msg "Removing ${service} ..."
     sudo systemctl stop "${service}"
     sudo systemctl disable "${service}"
@@ -336,6 +339,7 @@ function remove_octoprint_sudoers() {
 function remove_octoprint_env() {
   local files
   files=$(find "${HOME}" -maxdepth 1 -regextype posix-extended -regex "${HOME}/OctoPrint(_[0-9a-zA-Z]+)?" | sort)
+
   if [[ -n ${files} ]]; then
     for file in ${files}; do
       status_msg "Removing ${file} ..."
@@ -348,6 +352,7 @@ function remove_octoprint_env() {
 function remove_octoprint_dir() {
   local files
   files=$(find "${HOME}" -maxdepth 1 -regextype posix-extended -regex "${HOME}/.octoprint(_[0-9a-zA-Z]+)?" | sort)
+
   if [[ -n ${files} ]]; then
     for file in ${files}; do
       status_msg "Removing ${file} ..."
@@ -367,6 +372,7 @@ function remove_octoprint() {
   sed -i "/^octoprint_port=/d" "${INI_FILE}"
 
   local confirm="OctoPrint was successfully removed!"
+
   print_confirm "${confirm}" && return
 }
 
diff --git a/scripts/pretty_gcode.sh b/scripts/pretty_gcode.sh
index 3550565..8767da7 100644
--- a/scripts/pretty_gcode.sh
+++ b/scripts/pretty_gcode.sh
@@ -16,34 +16,33 @@ set -e
 #=================================================#
 
 function install_pgc_for_klipper() {
-  pgconfsrc="${PGC_DIR}/pgcode.local.conf"
-  pgconf="/etc/nginx/sites-available/pgcode.local.conf"
-  pgconfsl="/etc/nginx/sites-enabled/pgcode.local.conf"
-  pgc_default_port="7136"
+  local pgconfsrc="${PGC_DIR}/pgcode.local.conf"
+  local pgconf="/etc/nginx/sites-available/pgcode.local.conf"
+  local pgconfsl="/etc/nginx/sites-enabled/pgcode.local.conf"
+  local pgc_uri pgc_custom_port pgc_default_port="7136"
 
   status_msg "Installing PrettyGCode for Klipper ..."
-  ### let the user decide which port is used
   echo -e "${cyan}\n###### On which port should PrettyGCode run? (Default: ${pgc_default_port})${white} "
   read -e -p "${cyan}###### Port:${white} " -i "${pgc_default_port}" pgc_custom_port
+
   ### check nginx dependency
   local dep=(nginx)
   dependency_check "${dep[@]}"
-  ### clone repo
-  [ -d "${PGC_DIR}" ] && rm -rf "${PGC_DIR}"
+
+  [[ -d ${PGC_DIR} ]] && rm -rf "${PGC_DIR}"
   cd "${HOME}" && git clone "${PGC_REPO}"
-  ### copy nginx config into destination directory
   sudo cp "${pgconfsrc}" "${pgconf}"
-  ### replace default pi user in case the user is called different
   sudo sed -i "s|/home/pi/pgcode;|/home/${USER}/pgcode;|" "${pgconf}"
+
   ### replace default port
-  if [ "${pgc_custom_port}" != "${pgc_default_port}" ]; then
+  if (( pgc_custom_port != pgc_default_port )); then
     sudo sed -i "s|listen ${pgc_default_port};|listen ${pgc_custom_port};|" "${pgconf}"
     sudo sed -i "s|listen \[::\]:${pgc_default_port};|listen \[::\]:${pgc_custom_port};|" "${pgconf}"
   fi
-  ### create symlink
-  [ ! -L "${pgconfsl}" ] && sudo ln -s "${pgconf}" "${pgconfsl}"
+
+  [[ ! -L ${pgconfsl} ]] && sudo ln -s "${pgconf}" "${pgconfsl}"
   sudo systemctl restart nginx
-  ### show URI
+
   pgc_uri="http://$(hostname -I | cut -d" " -f1):${pgc_custom_port}"
   echo -e "${cyan}\n● Accessible via:${white} ${pgc_uri}"
   ok_msg "PrettyGCode for Klipper installed!\n"
@@ -54,17 +53,18 @@ function install_pgc_for_klipper() {
 #=================================================#
 
 function remove_prettygcode() {
-  pgconf="/etc/nginx/sites-available/pgcode.local.conf"
-  pgconfsl="/etc/nginx/sites-enabled/pgcode.local.conf"
-  if [ -d "${PGC_DIR}" ] || [ -f "${pgconf}" ] || [ -L "${pgconfsl}" ]; then
+  local pgconf="/etc/nginx/sites-available/pgcode.local.conf"
+  local pgconfsl="/etc/nginx/sites-enabled/pgcode.local.conf"
+
+  if [[ -d ${PGC_DIR} || -f ${pgconf} || -L ${pgconfsl} ]]; then
     status_msg "Removing PrettyGCode for Klipper ..."
     rm -rf "${PGC_DIR}"
     sudo rm -f "${pgconf}"
     sudo rm -f "${pgconfsl}"
     sudo systemctl restart nginx
-    CONFIRM_MSG="PrettyGCode for Klipper successfully removed!"
+    print_confirm "PrettyGCode for Klipper successfully removed!"
   else
-    ERROR_MSG="PrettyGCode for Klipper not found!\n Skipping..."
+    print_error "PrettyGCode for Klipper not found!\n Skipping..."
   fi
 }
 
@@ -73,6 +73,8 @@ function remove_prettygcode() {
 #=================================================#
 
 function update_pgc_for_klipper() {
+  [[ ! -d ${PGC_DIR} ]] && return
+
   status_msg "Updating PrettyGCode for Klipper ..."
   cd "${PGC_DIR}" && git pull
   ok_msg "Update complete!"
@@ -84,7 +86,8 @@ function update_pgc_for_klipper() {
 
 function get_local_prettygcode_commit() {
   local commit
-  [ ! -d "${PGC_DIR}" ] || [ ! -d "${PGC_DIR}"/.git ] && return
+
+  [[ ! -d ${PGC_DIR} || ! -d "${PGC_DIR}/.git" ]] && return
   cd "${PGC_DIR}"
   commit="$(git describe HEAD --always --tags | cut -d "-" -f 1,2)"
   echo "${commit}"
@@ -92,7 +95,8 @@ function get_local_prettygcode_commit() {
 
 function get_remote_prettygcode_commit() {
   local commit
-  [ ! -d "${PGC_DIR}" ] || [ ! -d "${PGC_DIR}"/.git ] && return
+
+  [[ ! -d ${PGC_DIR} || ! -d "${PGC_DIR}/.git" ]] && return
   cd "${PGC_DIR}" && git fetch origin -q
   commit=$(git describe origin/master --always --tags | cut -d "-" -f 1,2)
   echo "${commit}"
@@ -103,7 +107,8 @@ function compare_prettygcode_versions() {
   local versions local_ver remote_ver
   local_ver="$(get_local_prettygcode_commit)"
   remote_ver="$(get_remote_prettygcode_commit)"
-  if [ "${local_ver}" != "${remote_ver}" ]; then
+
+  if [[ ${local_ver} != "${remote_ver}" ]]; then
     versions="${yellow}$(printf " %-14s" "${local_ver}")${white}"
     versions+="|${green}$(printf " %-13s" "${remote_ver}")${white}"
     # add prettygcode to the update all array for the update all function in the updater
@@ -113,5 +118,6 @@ function compare_prettygcode_versions() {
     versions+="|${green}$(printf " %-13s" "${remote_ver}")${white}"
     PGC_UPDATE_AVAIL="false"
   fi
+
   echo "${versions}"
 }
\ No newline at end of file
diff --git a/scripts/rollback.sh b/scripts/rollback.sh
index 2ae40bb..33c41e1 100755
--- a/scripts/rollback.sh
+++ b/scripts/rollback.sh
@@ -23,6 +23,7 @@ function rollback_menu() {
   echo -e "| 2) Rollback Moonraker                                 |"
   back_footer
 
+  local action
   while true; do
     read -p "${cyan}###### Perform action:${white} " action
     case "${action}" in
@@ -45,7 +46,7 @@ function rollback_menu() {
 function rollback_component() {
   local component=${1}
 
-  if [ ! -d "${HOME}/${component}" ]; then
+  if [[ ! -d "${HOME}/${component}" ]]; then
     print_error "Rollback not possible! Missing installation?"
     return
   fi
@@ -53,7 +54,7 @@ function rollback_component() {
   echo
   top_border
   echo -e "| Please select how many commits you want to revert.    |"
-  echo -e "| Consider using the information provided by the Github |"
+  echo -e "| Consider using the information provided by the GitHub |"
   echo -e "| commit history to decide how many commits to revert.  |"
   blank_line
   echo -e "| ${red}Warning:${white}                                              |"
@@ -61,9 +62,10 @@ function rollback_component() {
   echo -e "| ${red}of printing! Proceeding WILL terminate that print!${white}    |"
   back_footer
 
+  local count
   while true; do
     read -p "${cyan}###### Revert this amount of commits:${white} " count
-    if [ -n "${count}" ] && ((count > 0)); then
+    if [[ -n ${count} ]] && ((count > 0)); then
       status_msg "Revert ${component^} by ${count} commits ..."
       cd "${HOME}/${component}"
       if git reset --hard HEAD~"${count}"; then
@@ -73,7 +75,7 @@ function rollback_component() {
         print_error "Reverting ${component^} failed! Please see the console output above."
       fi
       break
-    elif [[ "${count}" == "B" || "${count}" == "b" ]]; then
+    elif [[ ${count} == "B" || ${count} == "b" ]]; then
       clear && print_header && break
     else
       error_msg "Invalid command!"
diff --git a/scripts/switch_klipper_repo.sh b/scripts/switch_klipper_repo.sh
index 2c5c2a5..f8613bf 100644
--- a/scripts/switch_klipper_repo.sh
+++ b/scripts/switch_klipper_repo.sh
@@ -25,7 +25,7 @@ function change_klipper_repo_menu() {
     repo=$(echo "${repo}" | sed -r "s/^http(s)?:\/\/github.com\///" | sed "s/\.git$//" )
     repos+=("${repo}")
     ### if branch is not given, default to 'master'
-    [ -z "${branch}" ] && branch="master"
+    [[ -z ${branch} ]] && branch="master"
     branches+=("${branch}")
   done < <(grep -E "^[^#]" "${repo_file}")
 
@@ -37,23 +37,26 @@ function change_klipper_repo_menu() {
   local i=0
   for _ in "${repos[@]}"; do
     printf "| %s) %-63s|\n" "${i}" "${yellow}${repos[${i}]}${white} → ${branches[${i}]}"
-    i=$((i+1))
+    i=$(( i + 1 ))
   done
   blank_line
   back_help_footer
 
+  local option
   while true; do
     read -p "${cyan}###### Perform action:${white} " option
     case "${option}" in
-      0 | "$((option < ${#repos[@]}))")
+      0 | "$(( option < ${#repos[@]} ))")
         select_msg "Repo: ${repos[option]} Branch: ${branches[option]}"
-        if [ -d "${KLIPPER_DIR}" ]; then
+        if [[ -d ${KLIPPER_DIR} ]]; then
           top_border
           echo -e "|                   ${red}!!! ATTENTION !!!${white}                   |"
           echo -e "| Existing Klipper folder found! Proceeding will remove | "
           echo -e "| the existing Klipper folder and replace it with a     | "
           echo -e "| clean copy of the previously selected source repo!    | "
           bottom_border
+
+          local yn
           while true; do
           read -p "${cyan}###### Proceed? (Y/n):${white} " yn
             case "${yn}" in
@@ -97,12 +100,15 @@ function change_klipper_repo_menu() {
 function switch_klipper_repo() {
   local repo_url branch
   repo_url="https://github.com/${1}" branch=${2}
+
   status_msg "Switching Klipper repository..."
   do_action_service "stop" "klipper"
+
   cd "${HOME}"
-  [ -d "${KLIPPER_DIR}" ] && rm -rf "${KLIPPER_DIR}"
+  [[ -d ${KLIPPER_DIR} ]] && rm -rf "${KLIPPER_DIR}"
   git clone "${repo_url}" "klipper" && cd "${KLIPPER_DIR}"
   git checkout "${branch}" && cd "${HOME}"
+
   do_action_service "start" "klipper"
 }
 
@@ -119,6 +125,8 @@ function show_custom_klipper_repo_help() {
   echo -e "| An example file is provided at the same location.     |"
   blank_line
   back_footer
+
+  local choice
   while true; do
     read -p "${cyan}###### Please select:${white} " choice
     case "${choice}" in
diff --git a/scripts/ui/advanced_menu.sh b/scripts/ui/advanced_menu.sh
index 0f8f27e..ff9c6c1 100755
--- a/scripts/ui/advanced_menu.sh
+++ b/scripts/ui/advanced_menu.sh
@@ -28,6 +28,8 @@ function advanced_ui() {
 
 function advanced_menu() {
   do_action "" "advanced_ui"
+
+  local action
   while true; do
     read -p "${cyan}####### Perform action:${white} " action
     case "${action}" in
diff --git a/scripts/ui/backup_menu.sh b/scripts/ui/backup_menu.sh
index 193e078..9beda19 100755
--- a/scripts/ui/backup_menu.sh
+++ b/scripts/ui/backup_menu.sh
@@ -31,6 +31,8 @@ function backup_ui() {
 
 function backup_menu() {
   do_action "" "backup_ui"
+
+  local action
   while true; do
     read -p "${cyan}####### Perform action:${white} " action
     case "${action}" in
diff --git a/scripts/ui/install_menu.sh b/scripts/ui/install_menu.sh
index 08b4529..2a7bee6 100755
--- a/scripts/ui/install_menu.sh
+++ b/scripts/ui/install_menu.sh
@@ -36,6 +36,7 @@ function install_menu() {
   clear && print_header
   install_ui
 
+  local action
   while true; do
     read -p "${cyan}####### Perform action:${white} " action
     case "${action}" in
diff --git a/scripts/ui/main_menu.sh b/scripts/ui/main_menu.sh
index 9ed9695..5a6034a 100755
--- a/scripts/ui/main_menu.sh
+++ b/scripts/ui/main_menu.sh
@@ -45,34 +45,39 @@ function print_kiauh_version() {
 function print_status() {
   local status component="${1}"
   status=$(get_"${component}"_status)
-  if [ "${status}" == "Not installed!" ]; then
+
+  if [[ ${status} == "Not installed!" ]]; then
     status="${red}${status}${white}"
-  elif [ "${status}" == "Incomplete!" ]; then
+  elif [[ ${status} == "Incomplete!" ]]; then
     status="${yellow}${status}${white}"
   else
     status="${green}${status}${white}"
   fi
+
   printf "%-28s" "${status}"
 }
 
 function print_klipper_repo() {
   read_kiauh_ini
+
   local repo klipper_status
   klipper_status=$(get_klipper_status)
-  repo=$(echo ${custom_klipper_repo} | sed "s/https:\/\/github\.com\///" | sed "s/\.git$//")
+  repo=$(echo "${custom_klipper_repo}" | sed "s/https:\/\/github\.com\///" | sed "s/\.git$//")
   repo="${repo^^}"
-  if [[ "${klipper_status}" == "Not installed!" ]]; then
+
+  if [[ ${klipper_status} == "Not installed!" ]]; then
     repo="${red}-${white}"
-  elif [[ -n "${repo}" && "${repo}" != "KLIPPER3D/KLIPPER"  ]]; then
+  elif [[ -n ${repo} && ${repo} != "KLIPPER3D/KLIPPER"  ]]; then
     repo="${cyan}custom${white}"
   else
     repo="${cyan}Klipper3d/klipper${white}"
   fi
+
   printf "%-28s" "${repo}"
 }
 
 function kiauh_update_dialog() {
-  [ ! "$(kiauh_update_avail)" == "true" ] && return
+  [[ ! $(kiauh_update_avail) == "true" ]] && return
   top_border
   echo -e "|${green}              New KIAUH update available!              ${white}|"
   hr
@@ -82,15 +87,18 @@ function kiauh_update_dialog() {
   echo -e "|${yellow}  usually contain bugfixes, important changes or new   ${white}|"
   echo -e "|${yellow}  features. Please consider updating!                  ${white}|"
   bottom_border
+
+  local yn
   read -p "${cyan}Do you want to update now? (Y/n):${white} " yn
   while true; do
     case "${yn}" in
-    Y|y|Yes|yes|"")
-      do_action "update_kiauh"
-      break;;
-    N|n|No|no) break;;
-    *)
-      deny_action "kiauh_update_dialog";;
+      Y|y|Yes|yes|"")
+        do_action "update_kiauh"
+        break;;
+      N|n|No|no)
+        break;;
+      *)
+        deny_action "kiauh_update_dialog";;
     esac
   done
 }
@@ -100,6 +108,8 @@ function main_menu() {
   #prompt for KIAUH update if update available
   kiauh_update_dialog
   main_ui
+
+  local action
   while true; do
     read -p "${cyan}####### Perform action:${white} " action
     case "${action}" in
diff --git a/scripts/ui/remove_menu.sh b/scripts/ui/remove_menu.sh
index d74b51a..2a3ec18 100755
--- a/scripts/ui/remove_menu.sh
+++ b/scripts/ui/remove_menu.sh
@@ -32,6 +32,8 @@ function remove_ui() {
 
 function remove_menu() {
   do_action "" "remove_ui"
+
+  local action
   while true; do
     read -p "${cyan}####### Perform action:${white} " action
     case "${action}" in
diff --git a/scripts/ui/settings_menu.sh b/scripts/ui/settings_menu.sh
index c1b8740..a240a72 100755
--- a/scripts/ui/settings_menu.sh
+++ b/scripts/ui/settings_menu.sh
@@ -13,6 +13,7 @@ set -e
 
 function settings_ui() {
   read_kiauh_ini "${FUNCNAME[0]}"
+
   local custom_cfg_loc="${custom_klipper_cfg_loc}"
   local custom_repo="${custom_klipper_repo}"
   local custom_branch="${custom_klipper_repo_branch}"
@@ -21,37 +22,42 @@ function settings_ui() {
   local bbu="${backup_before_update}"
 
   ### config location
-  if [ -z "${custom_cfg_loc}" ]; then
+  if [[ -z ${custom_cfg_loc} ]]; then
     custom_cfg_loc="${cyan}${KLIPPER_CONFIG}${white}"
   else
     custom_cfg_loc="${cyan}${custom_cfg_loc}${white}"
   fi
+
   ### custom repository
   custom_repo=$(echo "${custom_repo}" | sed "s/https:\/\/github\.com\///" | sed "s/\.git$//" )
-  if [ -z "${custom_repo}" ]; then
+  if [[ -z ${custom_repo} ]]; then
     custom_repo="${cyan}Klipper3D/klipper${white}"
   else
     custom_repo="${cyan}${custom_repo}${white}"
   fi
+
   ### custom repository branch
-  if [ -z "${custom_branch}" ]; then
+  if [[ -z ${custom_branch} ]]; then
     custom_branch="${cyan}master${white}"
   else
     custom_branch="${cyan}${custom_branch}${white}"
   fi
+
   ### webinterface stable toggle
-  if [ "${ms_pre_rls}" == "false" ]; then
+  if [[ ${ms_pre_rls} == "false" ]]; then
     ms_pre_rls="${red}● ${ms_pre_rls}${white}"
   else
     ms_pre_rls="${green}● ${ms_pre_rls}${white}"
   fi
-  if [ "${fl_pre_rls}" == "false" ]; then
+
+  if [[ ${fl_pre_rls} == "false" ]]; then
     fl_pre_rls="${red}● ${fl_pre_rls}${white}"
   else
     fl_pre_rls="${green}● ${fl_pre_rls}${white}"
   fi
+
   ### backup before update toggle
-  if [ "${bbu}" == "false" ]; then
+  if [[ "${bbu}" == "false" ]]; then
     bbu="${red}● ${bbu}${white}"
   else
     bbu="${green}● ${bbu}${white}"
@@ -74,18 +80,18 @@ function settings_ui() {
   echo -e "| 1) Change Klipper config folder location              |"
   echo -e "| 2) Set custom Klipper repository                      |"
   blank_line
-  if [ "${mainsail_install_unstable}" == "false" ]; then
+  if [[ ${mainsail_install_unstable} == "false" ]]; then
   echo -e "| 3) ${green}Allow${white} unstable Mainsail releases                   |"
   else
   echo -e "| 3) ${red}Disallow${white} unstable Mainsail releases                |"
   fi
-  if [ "${fluidd_install_unstable}" == "false" ]; then
+  if [[ ${fluidd_install_unstable} == "false" ]]; then
   echo -e "| 4) ${green}Allow${white} unstable Fluidd releases                     |"
   else
   echo -e "| 4) ${red}Disallow${white} unstable Fluidd releases                  |"
   fi
   blank_line
-  if [ "${backup_before_update}" == "false" ]; then
+  if [[ ${backup_before_update} == "false" ]]; then
   echo -e "| 5) ${green}Enable${white} automatic backups before updates            |"
   else
   echo -e "| 5) ${red}Disable${white} automatic backups before updates           |"
@@ -94,7 +100,7 @@ function settings_ui() {
 }
 
 function show_settings_help() {
-  local choice default_cfg="${cyan}${HOME}/klipper_config${white}"
+  local default_cfg="${cyan}${HOME}/klipper_config${white}"
 
   top_border
   echo -e "|    ~~~~~~ < ? > Help: KIAUH Settings < ? > ~~~~~~     |"
@@ -131,6 +137,7 @@ function show_settings_help() {
   blank_line
   back_footer
 
+  local choice
   while true; do
     read -p "${cyan}###### Please select:${white} " choice
     case "${choice}" in
@@ -145,11 +152,10 @@ function show_settings_help() {
 }
 
 function settings_menu() {
-  local action
-
   clear && print_header
   settings_ui
 
+  local action
   while true; do
     read -p "${cyan}####### Perform action:${white} " action
     case "${action}" in
diff --git a/scripts/ui/update_menu.sh b/scripts/ui/update_menu.sh
index 785e278..5a6f632 100755
--- a/scripts/ui/update_menu.sh
+++ b/scripts/ui/update_menu.sh
@@ -39,6 +39,8 @@ function update_ui() {
 function update_menu() {
   unset update_arr
   do_action "" "update_ui"
+  
+  local action
   while true; do
     read -p "${cyan}####### Perform action:${white} " action
     case "${action}" in
@@ -73,44 +75,48 @@ function update_menu() {
 
 function update_all() {
   while true; do
-    if [ "${#update_arr[@]}" = "0" ]; then
-      CONFIRM_MSG="Everything is already up to date!"
+    if (( ${#update_arr[@]} == 0 )); then
+      print_confirm "Everything is already up-to-date!"
       echo; break
     fi
+    
     echo
     top_border
     echo -e "|  The following installations will be updated:         |"
-    if [ "$KLIPPER_UPDATE_AVAIL" = "true" ]; then
+    if [[ "${KLIPPER_UPDATE_AVAIL}" = "true" ]]; then
       echo -e "|  ${cyan}● Klipper${white}                                            |"
     fi
-    if [ "${MOONRAKER_UPDATE_AVAIL}" = "true" ]; then
+    if [[ "${MOONRAKER_UPDATE_AVAIL}" = "true" ]]; then
       echo -e "|  ${cyan}● Moonraker${white}                                          |"
     fi
-    if [ "${MAINSAIL_UPDATE_AVAIL}" = "true" ]; then
+    if [[ "${MAINSAIL_UPDATE_AVAIL}" = "true" ]]; then
       echo -e "|  ${cyan}● Mainsail${white}                                           |"
     fi
-    if [ "${FLUIDD_UPDATE_AVAIL}" = "true" ]; then
+    if [[ "${FLUIDD_UPDATE_AVAIL}" = "true" ]]; then
       echo -e "|  ${cyan}● Fluidd${white}                                             |"
     fi
-    if [ "${KLIPPERSCREEN_UPDATE_AVAIL}" = "true" ]; then
+    if [[ "${KLIPPERSCREEN_UPDATE_AVAIL}" = "true" ]]; then
       echo -e "|  ${cyan}● KlipperScreen${white}                                      |"
     fi
-    if [ "${PGC_UPDATE_AVAIL}" = "true" ]; then
+    if [[ "${PGC_UPDATE_AVAIL}" = "true" ]]; then
       echo -e "|  ${cyan}● PrettyGCode for Klipper${white}                            |"
     fi
-    if [ "${MOONRAKER_TELEGRAM_BOT_UPDATE_AVAIL}" = "true" ]; then
+    if [[ "${MOONRAKER_TELEGRAM_BOT_UPDATE_AVAIL}" = "true" ]]; then
       echo -e "|  ${cyan}● MoonrakerTelegramBot${white}                               |"
     fi
-    if [ "${SYS_UPDATE_AVAIL}" = "true" ]; then
+    if [[ "${SYS_UPDATE_AVAIL}" = "true" ]]; then
       echo -e "|  ${cyan}● System${white}                                             |"
     fi
     bottom_border
-    if [ "${#update_arr[@]}" != "0" ]; then
+    
+    local yn
+    if (( ${#update_arr[@]} != 0 )); then
       read -p "${cyan}###### Do you want to proceed? (Y/n):${white} " yn
-      case "$yn" in
+      case "${yn}" in
         Y|y|Yes|yes|"")
           for update in "${update_arr[@]}"
           do
+            #shellcheck disable=SC2250
             $update
           done
           break;;
diff --git a/scripts/upload_log.sh b/scripts/upload_log.sh
index 3c3b9b3..e802eb0 100755
--- a/scripts/upload_log.sh
+++ b/scripts/upload_log.sh
@@ -27,6 +27,8 @@ function accept_upload_conditions() {
   blank_line
   echo -e "| Do ${red}NOT${white} use this function if you don't agree!          |"
   bottom_border
+
+  local yn
   while true; do
     read -p "${cyan}Do you accept? (Y/n):${white} " yn
     case "${yn}" in
@@ -47,11 +49,12 @@ function accept_upload_conditions() {
 
 function upload_selection() {
   read_kiauh_ini "${FUNCNAME[0]}"
+
   local upload_agreed="${logupload_accepted}"
-  [ "${upload_agreed}" = "false" ] && accept_upload_conditions
+  [[ ${upload_agreed} == "false" ]] && accept_upload_conditions
 
   local logfiles
-  local klipper_logs="${KLIPPER_LOGS}"
+  local logs_dir="${KLIPPER_LOGS}"
   local webif_logs="/var/log/nginx"
 
   function find_logfile() {
@@ -62,9 +65,9 @@ function upload_selection() {
   }
 
   find_logfile "kiauh.log" "/tmp"
-  find_logfile "klippy*.log" "${klipper_logs}"
-  find_logfile "moonraker*.log" "${klipper_logs}"
-  find_logfile "telegram*.log" "${klipper_logs}"
+  find_logfile "klippy*.log" "${logs_dir}"
+  find_logfile "moonraker*.log" "${logs_dir}"
+  find_logfile "telegram*.log" "${logs_dir}"
   find_logfile "mainsail*" "${webif_logs}"
   find_logfile "fluidd*" "${webif_logs}"
   find_logfile "KlipperScreen.log" "/tmp"
@@ -77,20 +80,25 @@ function upload_selection() {
   hr
   echo -e "| You can choose the following logfiles for uploading:  |"
   blank_line
+
   for log in "${logfiles[@]}"; do
     log=${log//${HOME}/"~"}
-     ((i < 10)) && printf "|  ${i}) %-50s|\n" "${log}"
-    ((i >= 10)) && printf "| ${i}) %-50s|\n" "${log}"
-    i=$((i + 1))
+    (( i < 10 )) && printf "|  ${i}) %-50s|\n" "${log}"
+    (( i >= 10 )) && printf "| ${i}) %-50s|\n" "${log}"
+    i=$(( i + 1 ))
   done
+
   blank_line
   back_footer
+
+  local option
   while true; do
     read -p "${cyan}###### Please select:${white} " option
-    if [[ -n "${option}" && "${option}" -ge 0 && "${option}" -lt "${#logfiles[@]}" ]]; then
+
+    if [[ -n ${option} && ${option} -ge 0 && ${option} -lt ${#logfiles[@]} ]]; then
       upload_log "${logfiles[${option}]}"
       upload_selection
-    elif [[ "${option}" == "B" || "${option}" == "b" ]]; then
+    elif [[ ${option} == "B" || ${option} == "b" ]]; then
       return
     else
       error_msg "Invalid command!"
@@ -103,7 +111,8 @@ function upload_log() {
   clear && print_header
   status_msg "Uploading ${1} ..."
   link=$(curl -s -H "x-random;" --upload-file "${1}" 'http://paste.c-net.org/')
-  if [ -n "${link}" ]; then
+
+  if [[ -n ${link} ]]; then
     ok_msg "${1} upload successfull!"
     echo -e "\n${cyan}###### Here is your link:${white}"
     echo -e ">>>>>> ${link}\n"
diff --git a/scripts/utilities.sh b/scripts/utilities.sh
index 4eaecbd..883df84 100644
--- a/scripts/utilities.sh
+++ b/scripts/utilities.sh
@@ -16,8 +16,7 @@ set -e
 #================================================#
 
 function check_euid() {
-  if [[ ${EUID} -eq 0 ]]
-  then
+  if [[ ${EUID} -eq 0 ]]; then
     echo -e "${red}"
     top_border
     echo -e "|       !!! THIS SCRIPT MUST NOT RUN AS ROOT !!!        |"
@@ -55,6 +54,7 @@ function title_msg() {
 
 function print_error() {
   [[ -z ${1} ]] && return
+
   echo -e "${red}"
   echo -e "#=======================================================#"
   echo -e " ${1} "
@@ -64,6 +64,7 @@ function print_error() {
 
 function print_confirm() {
   [[ -z ${1} ]] && return
+
   echo -e "${green}"
   echo -e "#=======================================================#"
   echo -e " ${1} "
@@ -111,11 +112,13 @@ function log_error() {
 
 function read_kiauh_ini() {
   local func=${1}
+
   if [[ ! -f ${INI_FILE} ]]; then
     print_error "ERROR: File '~/.kiauh.ini' not found!"
     log_error "Reading from .kiauh.ini failed! File not found!"
     return 1
   fi
+
   log_info "Reading from .kiauh.ini ... (${func})"
   source "${INI_FILE}"
 }
@@ -125,6 +128,7 @@ function init_ini() {
   if [[ -f ${INI_FILE} ]] && ! grep -Eq "^# KIAUH v4\.0\.0$" "${INI_FILE}"; then
     rm "${INI_FILE}"
   fi
+
   ### initialize v4.0.0 ini file
   if [[ ! -f ${INI_FILE} ]]; then
     {
@@ -137,27 +141,35 @@ function init_ini() {
       echo -e "# KIAUH v4.0.0"
     } >> "${INI_FILE}"
   fi
+
   if ! grep -Eq "^backup_before_update=." "${INI_FILE}"; then
     echo -e "\nbackup_before_update=false\c" >> "${INI_FILE}"
   fi
+
   if ! grep -Eq "^logupload_accepted=." "${INI_FILE}"; then
     echo -e "\nlogupload_accepted=false\c" >> "${INI_FILE}"
   fi
+
   if ! grep -Eq "^custom_klipper_cfg_loc=" "${INI_FILE}"; then
     echo -e "\ncustom_klipper_cfg_loc=\c" >> "${INI_FILE}"
   fi
+
   if ! grep -Eq "^custom_klipper_repo=" "${INI_FILE}"; then
     echo -e "\ncustom_klipper_repo=\c" >> "${INI_FILE}"
   fi
+
   if ! grep -Eq "^custom_klipper_repo_branch=" "${INI_FILE}"; then
     echo -e "\ncustom_klipper_repo_branch=\c" >> "${INI_FILE}"
   fi
+
   if ! grep -Eq "^mainsail_install_unstable=" "${INI_FILE}"; then
     echo -e "\nmainsail_install_unstable=false\c" >> "${INI_FILE}"
   fi
+
   if ! grep -Eq "^fluidd_install_unstable=" "${INI_FILE}"; then
     echo -e "\nfluidd_install_unstable=false\c" >> "${INI_FILE}"
   fi
+
   fetch_webui_ports
 }
 
@@ -166,6 +178,8 @@ function change_klipper_cfg_folder() {
   current_cfg_loc="$(get_klipper_cfg_dir)"
   example_loc=$(printf "%s/<your_config_folder>" "${HOME}")
   recommended_loc=$(printf "%s/klipper_config" "${HOME}")
+
+  local yn
   while true; do
     top_border
     echo -e "|  ${yellow}IMPORTANT:${white}                                           |"
@@ -217,7 +231,8 @@ function set_klipper_cfg_path() {
   ### copy config files to new klipper config folder
   if [[ -n ${current_cfg_loc} && -d ${current_cfg_loc} ]]; then
     status_msg "Copy config files to '${new_cfg_loc}' ..."
-    if [ ! -d "${new_cfg_loc}" ]; then
+
+    if [[ ! -d ${new_cfg_loc} ]]; then
       log_info "Copy process started"
       mkdir -p "${new_cfg_loc}"
       cd "${current_cfg_loc}"
@@ -230,10 +245,13 @@ function set_klipper_cfg_path() {
   fi
 
   klipper_services=$(klipper_systemd)
+
   if [[ -n ${klipper_services} ]]; then
     status_msg "Re-writing Klipper services to use new config file location ..."
+
     for service in ${klipper_services}; do
       if [[ ${service} = "/etc/systemd/system/klipper.service" ]]; then
+
         if grep "Environment=KLIPPER_CONFIG=" "${service}"; then
           ### single instance klipper service installed by kiauh v4 / MainsailOS > 0.5.0
           sudo sed -i -r "/KLIPPER_CONFIG=/ s|CONFIG=(.+)\/printer\.cfg|CONFIG=${new_cfg_loc}/printer\.cfg|" "${service}"
@@ -241,8 +259,10 @@ function set_klipper_cfg_path() {
           ### single instance klipper service installed by kiauh v3
           sudo sed -i -r "/ExecStart=/ s|klippy\.py (.+)\/printer\.cfg|klippy\.py ${new_cfg_loc}\/printer\.cfg|" "${service}"
         fi
+
       else
         instance=$(echo "${service}" | cut -d"-" -f2 | cut -d"." -f1)
+
         if grep "Environment=KLIPPER_CONFIG=" "${service}"; then
           ### multi instance klipper service installed by kiauh v4 / MainsailOS > 0.5.0
           sudo sed -i -r "/KLIPPER_CONFIG=/ s|CONFIG=(.+)\/printer_${instance}\/printer\.cfg|CONFIG=${new_cfg_loc}\/printer_${instance}\/printer\.cfg|" "${service}"
@@ -256,11 +276,14 @@ function set_klipper_cfg_path() {
   fi
 
   moonraker_services=$(moonraker_systemd)
+
   if [[ -n ${moonraker_services} ]]; then
     ### handle multi moonraker instance service file
     status_msg "Re-writing Moonraker services to use new config file location ..."
+
     for service in ${moonraker_services}; do
       if [[ ${service} = "/etc/systemd/system/moonraker.service" ]]; then
+
         if grep "Environment=MOONRAKER_CONF=" "${service}"; then
           ### single instance moonraker service installed by kiauh v4 / MainsailOS > 0.5.0
           sudo sed -i -r "/MOONRAKER_CONF=/ s|_CONF=(.+)\/moonraker\.conf|_CONF=${new_cfg_loc}\/moonraker\.conf|" "${service}"
@@ -268,8 +291,10 @@ function set_klipper_cfg_path() {
           ### single instance moonraker service installed by kiauh v3
           sudo sed -i -r "/ExecStart=/ s| -c (.+)\/moonraker\.conf| -c ${new_cfg_loc}\/moonraker\.conf|" "${service}"
         fi
+
       else
         instance=$(echo "${service}" | cut -d"-" -f2 | cut -d"." -f1)
+
         if grep "Environment=MOONRAKER_CONF=" "${service}"; then
           ### multi instance moonraker service installed by kiauh v4 / MainsailOS > 0.5.0
           sudo sed -i -r "/MOONRAKER_CONF=/ s|_CONF=(.+)\/printer_${instance}\/moonraker\.conf|_CONF=${new_cfg_loc}\/printer_${instance}\/moonraker\.conf|" "${service}"
@@ -279,7 +304,9 @@ function set_klipper_cfg_path() {
         fi
       fi
     done
+
     moonraker_configs=$(find "${new_cfg_loc}" -type f -name "moonraker.conf" | sort)
+
     ### replace old file path with new one in moonraker.conf
     local loc
     for conf in ${moonraker_configs}; do
@@ -300,6 +327,7 @@ function set_klipper_cfg_path() {
 function switch_mainsail_releasetype() {
   read_kiauh_ini "${FUNCNAME[0]}"
   local state="${mainsail_install_unstable}"
+
   if [[ ${state} == "false" ]]; then
     sed -i '/mainsail_install_unstable=/s/false/true/' "${INI_FILE}"
     log_info "mainsail_install_unstable changed (false -> true) "
@@ -312,6 +340,7 @@ function switch_mainsail_releasetype() {
 function switch_fluidd_releasetype() {
   read_kiauh_ini "${FUNCNAME[0]}"
   local state="${fluidd_install_unstable}"
+
   if [[ ${state} == "false" ]]; then
     sed -i '/fluidd_install_unstable=/s/false/true/' "${INI_FILE}"
     log_info "fluidd_install_unstable changed (false -> true) "
@@ -324,6 +353,7 @@ function switch_fluidd_releasetype() {
 function toggle_backup_before_update() {
   read_kiauh_ini "${FUNCNAME[0]}"
   local state="${backup_before_update}"
+
   if [[ ${state} = "false" ]]; then
     sed -i '/backup_before_update=/s/false/true/' "${INI_FILE}"
   else
@@ -334,6 +364,7 @@ function toggle_backup_before_update() {
 function set_custom_klipper_repo() {
   read_kiauh_ini "${FUNCNAME[0]}"
   local repo=${1} branch=${2}
+
   sed -i "/^custom_klipper_repo=/d" "${INI_FILE}"
   sed -i '$a'"custom_klipper_repo=${repo}" "${INI_FILE}"
   sed -i "/^custom_klipper_repo_branch=/d" "${INI_FILE}"
@@ -347,10 +378,12 @@ function set_custom_klipper_repo() {
 function do_action_service() {
   local services action=${1} service=${2}
   services=$(find "${SYSTEMD}" -maxdepth 1 -regextype posix-extended -regex "${SYSTEMD}/${service}(-[0-9a-zA-Z]+)?.service" | sort)
+
   if [[ -n ${services} ]]; then
     for service in ${services}; do
       service=$(echo "${service}" | rev | cut -d"/" -f1 | rev)
       status_msg "${action^} ${service} ..."
+
       if sudo systemctl "${action}" "${service}"; then
         log_info "${service}: ${action} > success"
         ok_msg "${action^} ${service} successfull!"
@@ -386,13 +419,14 @@ function dependency_check() {
   local dep=( "${@}" )
   local packages
   status_msg "Checking for the following dependencies:"
+
   #check if package is installed, if not write its name into array
   for pkg in "${dep[@]}"; do
     echo -e "${cyan}● ${pkg} ${white}"
-    if [[ ! $(dpkg-query -f'${Status}' --show "${pkg}" 2>/dev/null) = *\ installed ]]; then
-      packages+=("${pkg}")
-    fi
+    [[ ! $(dpkg-query -f'${Status}' --show "${pkg}" 2>/dev/null) = *\ installed ]] && \
+    packages+=("${pkg}")
   done
+
   #if array is not empty, install packages from array
   if (( ${#packages[@]} > 0 )); then
     status_msg "Installing the following dependencies:"
@@ -400,6 +434,7 @@ function dependency_check() {
       echo -e "${cyan}● ${package} ${white}"
     done
     echo
+
     if sudo apt-get update --allow-releaseinfo-change && sudo apt-get install "${packages[@]}" -y; then
       ok_msg "Dependencies installed!"
     else
@@ -414,24 +449,22 @@ function dependency_check() {
 
 function system_check_webui() {
   ### check system for an installed haproxy service
-  if [[ $(dpkg-query -f'${Status}' --show haproxy 2>/dev/null) = *\ installed ]]; then
-    HAPROXY_FOUND="true"
-  fi
+  [[ $(dpkg-query -f'${Status}' --show haproxy 2>/dev/null) = *\ installed ]] && \
+  HAPROXY_FOUND="true"
 
   ### check system for an installed lighttpd service
-  if [[ $(dpkg-query -f'${Status}' --show lighttpd 2>/dev/null) = *\ installed ]]; then
-    LIGHTTPD_FOUND="true"
-  fi
+  [[ $(dpkg-query -f'${Status}' --show lighttpd 2>/dev/null) = *\ installed ]] && \
+  LIGHTTPD_FOUND="true"
 
   ### check system for an installed apache2 service
-  if [[ $(dpkg-query -f'${Status}' --show apache2 2>/dev/null) = *\ installed ]]; then
-    APACHE2_FOUND="true"
-  fi
+  [[ $(dpkg-query -f'${Status}' --show apache2 2>/dev/null) = *\ installed ]] && \
+  APACHE2_FOUND="true"
 }
 
 function fetch_webui_ports() {
-  ### read ports from possible installed interfaces and write them to ~/.kiauh.ini
   local port interfaces=("mainsail" "fluidd" "octoprint")
+
+  ### read ports from possible installed interfaces and write them to ~/.kiauh.ini
   for interface in "${interfaces[@]}"; do
     if [[ -f "/etc/nginx/sites-available/${interface}" ]]; then
       port=$(grep -E "listen" "/etc/nginx/sites-available/${interface}" | head -1 | sed 's/^\s*//' | sed 's/;$//' | cut -d" " -f2)
@@ -454,6 +487,7 @@ function fetch_webui_ports() {
 function check_system_updates() {
   local updates_avail info_msg
   updates_avail=$(apt list --upgradeable 2>/dev/null | sed "1d")
+
   if [[ -n ${updates_avail} ]]; then
     # add system updates to the update all array for the update all function in the updater
     SYS_UPDATE_AVAIL="true" && update_arr+=(update_system)
@@ -462,6 +496,7 @@ function check_system_updates() {
     SYS_UPDATE_AVAIL="false"
     info_msg="${green}System up to date!       ${white}"
   fi
+
   echo "${info_msg}"
 }
 
@@ -476,12 +511,15 @@ function update_system() {
 
 function check_usergroups() {
   local group_dialout group_tty
+
   if grep -q "dialout" </etc/group && ! grep -q "dialout" <(groups "${USER}"); then
     group_dialout="false"
   fi
+
   if grep -q "tty" </etc/group && ! grep -q "tty" <(groups "${USER}"); then
     group_tty="false"
   fi
+
   if [[ ${group_dialout} == "false" || ${group_tty} == "false" ]] ; then
     top_border
     echo -e "| ${yellow}WARNING: Your current user is not in group:${white}           |"
@@ -499,6 +537,8 @@ function check_usergroups() {
     echo -e "| ${yellow}INFO:${white}                                                 |"
     echo -e "| ${yellow}Relog required for group assignments to take effect!${white}  |"
     bottom_border
+
+    local yn
     while true; do
       read -p "${cyan}###### Add user '${USER}' to group(s) now? (Y/n):${white} " yn
       case "${yn}" in
@@ -534,6 +574,8 @@ function set_custom_hostname() {
   echo -e "|        can open Mainsail / Fluidd / Octoprint by      |"
   echo -e "|        browsing to: http://my-printer.local           |"
   bottom_border
+
+  local yn
   while true; do
     read -p "${cyan}###### Do you want to change the hostname? (y/N):${white} " yn
     case "${yn}" in
@@ -558,9 +600,12 @@ function change_hostname() {
     echo -e "|  ${red}No special characters allowed!${white}                       |"
     echo -e "|  ${red}No leading or trailing '-' allowed!${white}                  |"
     bottom_border
+
     while true; do
       read -p "${cyan}###### Please set the new hostname:${white} " new_hostname
+
       if [[ ${new_hostname} =~ ${regex} ]]; then
+        local yn
         while true; do
           echo
           read -p "${cyan}###### Do you want '${new_hostname}' to be the new hostname? (Y/n):${white} " yn