diff --git a/scripts/install_klipper_webui.sh b/scripts/install_klipper_webui.sh
index 31f29a2..e9c7335 100755
--- a/scripts/install_klipper_webui.sh
+++ b/scripts/install_klipper_webui.sh
@@ -1,3 +1,16 @@
+#!/bin/bash
+
+#=======================================================================#
+# Copyright (C) 2020 - 2022 Dominik Willner <th33xitus@gmail.com>       #
+#                                                                       #
+# This file is part of KIAUH - Klipper Installation And Update Helper   #
+# https://github.com/th33xitus/kiauh                                    #
+#                                                                       #
+# This file may be distributed under the terms of the GNU GPLv3 license #
+#=======================================================================#
+
+set -e
+
 MAINSAIL_REPO_API="https://api.github.com/repos/mainsail-crew/mainsail/releases"
 FLUIDD_REPO_API="https://api.github.com/repos/fluidd-core/fluidd/releases"
 
@@ -38,7 +51,7 @@ get_user_selection_mjpg-streamer(){
     echo -e "|  Install MJGP-Streamer for webcam support?            |"
     bottom_border
     read -p "${cyan}###### Install MJPG-Streamer? (Y/n):${default} " yn
-    case "$yn" in
+    case "${yn}" in
       Y|y|Yes|yes|"")
         echo -e "###### > Yes"
         INSTALL_MJPG="true"
@@ -75,7 +88,7 @@ get_user_selection_kiauh_macros(){
     echo -e "| add the recommended example macros to your config.    |"
     bottom_border
     read -p "${cyan}###### Add the recommended macros? (Y/n):${default} " yn
-    case "$yn" in
+    case "${yn}" in
       Y|y|Yes|yes|"")
         echo -e "###### > Yes"
         ADD_KIAUH_MACROS="true"
@@ -108,18 +121,18 @@ install_webui(){
   [ "$1" == "fluidd" ] && IF_NAME1="Fluidd" && IF_NAME2="Fluidd       "
 
   ### exit mainsail/fluidd setup if moonraker not found
-  if [ $moonraker_chk_ok = "false" ]; then
+  if [ "${moonraker_chk_ok}" = "false" ]; then
     ERROR_MSG="Moonraker service not found!\n Please install Moonraker first!"
     print_msg && clear_msg && return 0
   fi
 
-  status_msg "Initializing $IF_NAME1 installation ..."
+  status_msg "Initializing ${IF_NAME1} installation ..."
   ### check for other enabled web interfaces
   unset SET_LISTEN_PORT
   detect_enabled_sites
 
   ### check if another site already listens to port 80
-  $1_port_check
+  "${1}"_port_check
 
   ### ask user to install mjpg-streamer
   if ! ls /etc/systemd/system/webcamd.service 2>/dev/null 1>&2; then
@@ -127,46 +140,46 @@ install_webui(){
   fi
 
   ### ask user to install the recommended webinterface macros
-  if ! ls "$klipper_cfg_loc"/kiauh_macros.cfg 2>/dev/null 1>&2 || ! ls "$klipper_cfg_loc"/printer_*/kiauh_macros.cfg 2>/dev/null 1>&2; then
-    get_user_selection_kiauh_macros "$IF_NAME2"
+  if ! ls "${klipper_cfg_loc}"/kiauh_macros.cfg 2>/dev/null 1>&2 || ! ls "${klipper_cfg_loc}"/printer_*/kiauh_macros.cfg 2>/dev/null 1>&2; then
+    get_user_selection_kiauh_macros "${IF_NAME2}"
   fi
   ### create /etc/nginx/conf.d/upstreams.conf
   set_upstream_nginx_cfg
   ### create /etc/nginx/sites-available/<interface config>
-  set_nginx_cfg "$1"
+  set_nginx_cfg "${1}"
 
   ### symlink nginx log
-  symlink_webui_nginx_log "$1"
+  symlink_webui_nginx_log "${1}"
 
   ### copy the kiauh_macros.cfg to the config location
   install_kiauh_macros
 
   ### install mainsail/fluidd
-  $1_setup
+  "${1}"_setup
 
   ### install mjpg-streamer
-  [ "$INSTALL_MJPG" = "true" ] && install_mjpg-streamer
+  [ "${INSTALL_MJPG}" = "true" ] && install_mjpg-streamer
 
   fetch_webui_ports #WIP
 
   ### confirm message
-  CONFIRM_MSG="$IF_NAME1 has been set up!"
+  CONFIRM_MSG="${IF_NAME1} has been set up!"
   print_msg && clear_msg
 }
 
 symlink_webui_nginx_log(){
   LPATH="${HOME}/klipper_logs"
-  UI_ACCESS_LOG="/var/log/nginx/$1-access.log"
-  UI_ERROR_LOG="/var/log/nginx/$1-error.log"
-  [ ! -d "$LPATH" ] && mkdir -p "$LPATH"
-  if [ -f "$UI_ACCESS_LOG" ] &&  [ ! -L "$LPATH/$1-access.log" ]; then
-    status_msg "Creating symlink for $UI_ACCESS_LOG ..."
-    ln -s "$UI_ACCESS_LOG" "$LPATH"
+  UI_ACCESS_LOG="/var/log/nginx/${1}-access.log"
+  UI_ERROR_LOG="/var/log/nginx/${1}-error.log"
+  [ ! -d "${LPATH}" ] && mkdir -p "${LPATH}"
+  if [ -f "${UI_ACCESS_LOG}" ] &&  [ ! -L "${LPATH}/${1}-access.log" ]; then
+    status_msg "Creating symlink for ${UI_ACCESS_LOG} ..."
+    ln -s "${UI_ACCESS_LOG}" "${LPATH}"
     ok_msg "OK!"
   fi
-  if [ -f "$UI_ERROR_LOG" ] &&  [ ! -L "$LPATH/$1-error.log" ]; then
-    status_msg "Creating symlink for $UI_ERROR_LOG ..."
-    ln -s "$UI_ERROR_LOG" "$LPATH"
+  if [ -f "${UI_ERROR_LOG}" ] &&  [ ! -L "${LPATH}/${1}-error.log" ]; then
+    status_msg "Creating symlink for ${UI_ERROR_LOG} ..."
+    ln -s "${UI_ERROR_LOG}" "${LPATH}"
     ok_msg "OK!"
   fi
 }
@@ -174,30 +187,30 @@ symlink_webui_nginx_log(){
 install_kiauh_macros(){
   source_kiauh_ini
   ### copy kiauh_macros.cfg
-  if [ "$ADD_KIAUH_MACROS" = "true" ]; then
+  if [ "${ADD_KIAUH_MACROS}" = "true" ]; then
     ### create a backup of the config folder
     backup_klipper_config_dir
     ### handle multi printer.cfg
-    if ls "$klipper_cfg_loc"/printer_* 2>/dev/null 1>&2; then
-      for config in $(find $klipper_cfg_loc/printer_*/printer.cfg); do
-        path=$(echo "$config" | rev | cut -d"/" -f2- | rev)
-        if [ ! -f "$path/kiauh_macros.cfg" ]; then
+    if ls "${klipper_cfg_loc}"/printer_* 2>/dev/null 1>&2; then
+      for config in $(find ${klipper_cfg_loc}/printer_*/printer.cfg); do
+        path=$(echo "${config}" | rev | cut -d"/" -f2- | rev)
+        if [ ! -f "${path}/kiauh_macros.cfg" ]; then
           ### copy kiauh_macros.cfg to config location
           status_msg "Creating macro config file ..."
-          cp "${SRCDIR}/kiauh/resources/kiauh_macros.cfg" "$path"
+          cp "${SRCDIR}/kiauh/resources/kiauh_macros.cfg" "${path}"
           ### write the include to the very first line of the printer.cfg
-          sed -i "1 i [include kiauh_macros.cfg]" "$path/printer.cfg"
-          ok_msg "$path/kiauh_macros.cfg created!"
+          sed -i "1 i [include kiauh_macros.cfg]" "${path}/printer.cfg"
+          ok_msg "${path}/kiauh_macros.cfg created!"
         fi
       done
     ### handle single printer.cfg
-    elif [ -f "$klipper_cfg_loc/printer.cfg" ] && [ ! -f "$klipper_cfg_loc/kiauh_macros.cfg" ]; then
+    elif [ -f "${klipper_cfg_loc}/printer.cfg" ] && [ ! -f "${klipper_cfg_loc}/kiauh_macros.cfg" ]; then
       ### copy kiauh_macros.cfg to config location
       status_msg "Creating macro config file ..."
-      cp "${SRCDIR}/kiauh/resources/kiauh_macros.cfg" "$klipper_cfg_loc"
+      cp "${SRCDIR}/kiauh/resources/kiauh_macros.cfg" "${klipper_cfg_loc}"
       ### write the include to the very first line of the printer.cfg
-      sed -i "1 i [include kiauh_macros.cfg]" "$klipper_cfg_loc/printer.cfg"
-      ok_msg "$klipper_cfg_loc/kiauh_macros.cfg created!"
+      sed -i "1 i [include kiauh_macros.cfg]" "${klipper_cfg_loc}/printer.cfg"
+      ok_msg "${klipper_cfg_loc}/kiauh_macros.cfg created!"
     fi
     ### restart klipper service to parse the modified printer.cfg
     do_action_service "restart" "klipper"
@@ -205,19 +218,19 @@ install_kiauh_macros(){
 }
 
 mainsail_port_check(){
-  if [ "$MAINSAIL_ENABLED" = "false" ]; then
-    if [ "$SITE_ENABLED" = "true" ]; then
+  if [ "${MAINSAIL_ENABLED}" = "false" ]; then
+    if [ "${SITE_ENABLED}" = "true" ]; then
       status_msg "Detected other enabled interfaces:"
-      [ "$OCTOPRINT_ENABLED" = "true" ] && echo -e "   ${cyan}● OctoPrint - Port: $OCTOPRINT_PORT${default}"
-      [ "$FLUIDD_ENABLED" = "true" ] && echo -e "   ${cyan}● Fluidd - Port: $FLUIDD_PORT${default}"
-      [ "$DWC2_ENABLED" = "true" ] && echo -e "   ${cyan}● DWC2 - Port: $DWC2_PORT${default}"
-      if [ "$FLUIDD_PORT" = "80" ] || [ "$DWC2_PORT" = "80" ] || [ "$OCTOPRINT_PORT" = "80" ]; then
+      [ "${OCTOPRINT_ENABLED}" = "true" ] && echo -e "   ${cyan}● OctoPrint - Port: ${OCTOPRINT_PORT}${default}"
+      [ "${FLUIDD_ENABLED}" = "true" ] && echo -e "   ${cyan}● Fluidd - Port: ${FLUIDD_PORT}${default}"
+      [ "${DWC2_ENABLED}" = "true" ] && echo -e "   ${cyan}● DWC2 - Port: ${DWC2_PORT}${default}"
+      if [ "${FLUIDD_PORT}" = "80" ] || [ "${DWC2_PORT}" = "80" ] || [ "${OCTOPRINT_PORT}" = "80" ]; then
         PORT_80_BLOCKED="true"
         select_mainsail_port
       fi
     else
       DEFAULT_PORT=$(grep listen "${SRCDIR}/kiauh/resources/klipper_webui_nginx.cfg" | head -1 | sed 's/^\s*//' | cut -d" " -f2 | cut -d";" -f1)
-      SET_LISTEN_PORT=$DEFAULT_PORT
+      SET_LISTEN_PORT=${DEFAULT_PORT}
     fi
     SET_NGINX_CFG="true"
   else
@@ -226,19 +239,19 @@ mainsail_port_check(){
 }
 
 fluidd_port_check(){
-  if [ "$FLUIDD_ENABLED" = "false" ]; then
-    if [ "$SITE_ENABLED" = "true" ]; then
+  if [ "${FLUIDD_ENABLED}" = "false" ]; then
+    if [ "${SITE_ENABLED}" = "true" ]; then
       status_msg "Detected other enabled interfaces:"
-      [ "$OCTOPRINT_ENABLED" = "true" ] && echo "   ${cyan}● OctoPrint - Port: $OCTOPRINT_PORT${default}"
-      [ "$MAINSAIL_ENABLED" = "true" ] && echo "   ${cyan}● Mainsail - Port: $MAINSAIL_PORT${default}"
-      [ "$DWC2_ENABLED" = "true" ] && echo "   ${cyan}● DWC2 - Port: $DWC2_PORT${default}"
-      if [ "$MAINSAIL_PORT" = "80" ] || [ "$DWC2_PORT" = "80" ] || [ "$OCTOPRINT_PORT" = "80" ]; then
+      [ "${OCTOPRINT_ENABLED}" = "true" ] && echo "   ${cyan}● OctoPrint - Port: ${OCTOPRINT_PORT}${default}"
+      [ "${MAINSAIL_ENABLED}" = "true" ] && echo "   ${cyan}● Mainsail - Port: ${MAINSAIL_PORT}${default}"
+      [ "${DWC2_ENABLED}" = "true" ] && echo "   ${cyan}● DWC2 - Port: ${DWC2_PORT}${default}"
+      if [ "${MAINSAIL_PORT}" = "80" ] || [ "${DWC2_PORT}" = "80" ] || [ "${OCTOPRINT_PORT}" = "80" ]; then
         PORT_80_BLOCKED="true"
         select_fluidd_port
       fi
     else
       DEFAULT_PORT=$(grep listen "${SRCDIR}/kiauh/resources/klipper_webui_nginx.cfg" | head -1 | sed 's/^\s*//' | cut -d" " -f2 | cut -d";" -f1)
-      SET_LISTEN_PORT=$DEFAULT_PORT
+      SET_LISTEN_PORT=${DEFAULT_PORT}
     fi
     SET_NGINX_CFG="true"
   else
@@ -247,16 +260,16 @@ fluidd_port_check(){
 }
 
 select_mainsail_port(){
-  if [ "$PORT_80_BLOCKED" = "true" ]; then
+  if [ "${PORT_80_BLOCKED}" = "true" ]; then
     echo
     top_border
     echo -e "|                    ${red}!!!WARNING!!!${default}                      |"
     echo -e "| ${red}You need to choose a different port for Mainsail!${default}     |"
     echo -e "| ${red}The following web interface is listening at port 80:${default}  |"
     blank_line
-    [ "$OCTOPRINT_PORT" = "80" ] && echo "|  ● OctoPrint                                          |"
-    [ "$FLUIDD_PORT" = "80" ] && echo "|  ● Fluidd                                             |"
-    [ "$DWC2_PORT" = "80" ] && echo "|  ● DWC2                                               |"
+    [ "${OCTOPRINT_PORT}" = "80" ] && echo "|  ● OctoPrint                                          |"
+    [ "${FLUIDD_PORT}" = "80" ] && echo "|  ● Fluidd                                             |"
+    [ "${DWC2_PORT}" = "80" ] && echo "|  ● DWC2                                               |"
     blank_line
     echo -e "| Make sure you don't choose a port which was already   |"
     echo -e "| assigned to one of the other webinterfaces and do ${red}NOT${default} |"
@@ -267,9 +280,9 @@ select_mainsail_port(){
     bottom_border
     while true; do
       read -p "${cyan}Please enter a new Port:${default} " NEW_PORT
-      if [ "$NEW_PORT" != "$FLUIDD_PORT" ] && [ "$NEW_PORT" != "$DWC2_PORT" ] && [ "$NEW_PORT" != "$OCTOPRINT_PORT" ]; then
-        echo "Setting port $NEW_PORT for Mainsail!"
-        SET_LISTEN_PORT=$NEW_PORT
+      if [ "${NEW_PORT}" != "${FLUIDD_PORT}" ] && [ "${NEW_PORT}" != "${DWC2_PORT}" ] && [ "${NEW_PORT}" != "${OCTOPRINT_PORT}" ]; then
+        echo "Setting port ${NEW_PORT} for Mainsail!"
+        SET_LISTEN_PORT=${NEW_PORT}
         break
       else
         echo "That port is already taken! Select a different one!"
@@ -279,16 +292,16 @@ select_mainsail_port(){
 }
 
 select_fluidd_port(){
-  if [ "$PORT_80_BLOCKED" = "true" ]; then
+  if [ "${PORT_80_BLOCKED}" = "true" ]; then
     echo
     top_border
     echo -e "|                    ${red}!!!WARNING!!!${default}                      |"
     echo -e "| ${red}You need to choose a different port for Fluidd!${default}       |"
     echo -e "| ${red}The following web interface is listening at port 80:${default}  |"
     blank_line
-    [ "$OCTOPRINT_PORT" = "80" ] && echo "|  ● OctoPrint                                          |"
-    [ "$MAINSAIL_PORT" = "80" ] && echo "|  ● Mainsail                                           |"
-    [ "$DWC2_PORT" = "80" ] && echo "|  ● DWC2                                               |"
+    [ "${OCTOPRINT_PORT}" = "80" ] && echo "|  ● OctoPrint                                          |"
+    [ "${MAINSAIL_PORT}" = "80" ] && echo "|  ● Mainsail                                           |"
+    [ "${DWC2_PORT}" = "80" ] && echo "|  ● DWC2                                               |"
     blank_line
     echo -e "| Make sure you don't choose a port which was already   |"
     echo -e "| assigned to one of the other webinterfaces and do ${red}NOT${default} |"
@@ -299,9 +312,9 @@ select_fluidd_port(){
     bottom_border
     while true; do
       read -p "${cyan}Please enter a new Port:${default} " NEW_PORT
-      if [ "$NEW_PORT" != "$MAINSAIL_PORT" ] && [ "$NEW_PORT" != "$DWC2_PORT" ] && [ "$NEW_PORT" != "$OCTOPRINT_PORT" ]; then
-        echo "Setting port $NEW_PORT for Fluidd!"
-        SET_LISTEN_PORT=$NEW_PORT
+      if [ "${NEW_PORT}" != "${MAINSAIL_PORT}" ] && [ "${NEW_PORT}" != "${DWC2_PORT}" ] && [ "${NEW_PORT}" != "${OCTOPRINT_PORT}" ]; then
+        echo "Setting port ${NEW_PORT} for Fluidd!"
+        SET_LISTEN_PORT=${NEW_PORT}
         break
       else
         echo "That port is already taken! Select a different one!"
@@ -311,22 +324,22 @@ select_fluidd_port(){
 }
 
 get_mainsail_ver(){
-  MAINSAIL_VERSION=$(curl -s $MAINSAIL_REPO_API | grep tag_name | cut -d'"' -f4 | head -1)
+  MAINSAIL_VERSION=$(curl -s "${MAINSAIL_REPO_API}" | grep tag_name | cut -d'"' -f4 | head -1)
 }
 
 get_fluidd_ver(){
-  FLUIDD_VERSION=$(curl -s $FLUIDD_REPO_API | grep tag_name | cut -d'"' -f4 | head -1)
+  FLUIDD_VERSION=$(curl -s "${FLUIDD_REPO_API}" | grep tag_name | cut -d'"' -f4 | head -1)
 }
 
 mainsail_setup(){
   ### get mainsail download url
-  MAINSAIL_DL_URL=$(curl -s $MAINSAIL_REPO_API | grep browser_download_url | cut -d'"' -f4 | head -1)
+  MAINSAIL_DL_URL=$(curl -s "${MAINSAIL_REPO_API}" | grep browser_download_url | cut -d'"' -f4 | head -1)
 
   ### remove existing and create fresh mainsail folder, then download mainsail
-  [ -d "$MAINSAIL_DIR" ] && rm -rf "$MAINSAIL_DIR"
-  mkdir "$MAINSAIL_DIR" && cd $MAINSAIL_DIR
-  status_msg "Downloading Mainsail $MAINSAIL_VERSION ..."
-  wget "$MAINSAIL_DL_URL" && ok_msg "Download complete!"
+  [ -d "${MAINSAIL_DIR}" ] && rm -rf "${MAINSAIL_DIR}"
+  mkdir "${MAINSAIL_DIR}" && cd "${MAINSAIL_DIR}"
+  status_msg "Downloading Mainsail ${MAINSAIL_VERSION} ..."
+  wget "${MAINSAIL_DL_URL}" && ok_msg "Download complete!"
 
   ### extract archive
   status_msg "Extracting archive ..."
@@ -343,19 +356,19 @@ mainsail_setup(){
 }
 
 enable_mainsail_remotemode(){
-  rm -f "$MAINSAIL_DIR/config.json"
-  echo -e "{\n    \"remoteMode\":true\n}" >> "$MAINSAIL_DIR/config.json"
+  rm -f "${MAINSAIL_DIR}/config.json"
+  echo -e "{\n    \"remoteMode\":true\n}" >> "${MAINSAIL_DIR}/config.json"
 }
 
 fluidd_setup(){
   ### get fluidd download url
-  FLUIDD_DL_URL=$(curl -s $FLUIDD_REPO_API | grep browser_download_url | cut -d'"' -f4 | head -1)
+  FLUIDD_DL_URL=$(curl -s "${FLUIDD_REPO_API}" | grep browser_download_url | cut -d'"' -f4 | head -1)
 
   ### remove existing and create fresh fluidd folder, then download fluidd
-  [ -d "$FLUIDD_DIR" ] && rm -rf "$FLUIDD_DIR"
-  mkdir "$FLUIDD_DIR" && cd $FLUIDD_DIR
-  status_msg "Downloading Fluidd $FLUIDD_VERSION ..."
-  wget "$FLUIDD_DL_URL" && ok_msg "Download complete!"
+  [ -d "${FLUIDD_DIR}" ] && rm -rf "${FLUIDD_DIR}"
+  mkdir "${FLUIDD_DIR}" && cd "${FLUIDD_DIR}"
+  status_msg "Downloading Fluidd ${FLUIDD_VERSION} ..."
+  wget "${FLUIDD_DL_URL}" && ok_msg "Download complete!"
 
   ### extract archive
   status_msg "Extracting archive ..."
@@ -369,19 +382,19 @@ fluidd_setup(){
 set_upstream_nginx_cfg(){
   get_date
   ### backup existing nginx configs
-  [ ! -d "$BACKUP_DIR/nginx_cfg" ] && mkdir -p "$BACKUP_DIR/nginx_cfg"
-  [ -f "$NGINX_CONFD/upstreams.conf" ] && sudo mv "$NGINX_CONFD/upstreams.conf" "$BACKUP_DIR/nginx_cfg/${current_date}_upstreams.conf"
-  [ -f "$NGINX_CONFD/common_vars.conf" ] && sudo mv "$NGINX_CONFD/common_vars.conf" "$BACKUP_DIR/nginx_cfg/${current_date}_common_vars.conf"
+  [ ! -d "${BACKUP_DIR}/nginx_cfg" ] && mkdir -p "${BACKUP_DIR}/nginx_cfg"
+  [ -f "${NGINX_CONFD}/upstreams.conf" ] && sudo mv "${NGINX_CONFD}/upstreams.conf" "${BACKUP_DIR}/nginx_cfg/${current_date}_upstreams.conf"
+  [ -f "${NGINX_CONFD}/common_vars.conf" ] && sudo mv "${NGINX_CONFD}/common_vars.conf" "${BACKUP_DIR}/nginx_cfg/${current_date}_common_vars.conf"
   ### transfer ownership of backed up files from root to ${USER}
   for log in $(ls "$BACKUP_DIR/nginx_cfg"); do
-    sudo chown "${USER}" "$BACKUP_DIR/nginx_cfg/$log"
+    sudo chown "${USER}" "${BACKUP_DIR}/nginx_cfg/$log"
   done
   ### copy nginx configs to target destination
-  if [ ! -f "$NGINX_CONFD/upstreams.conf" ]; then
-    sudo cp "${SRCDIR}/kiauh/resources/upstreams.conf" "$NGINX_CONFD"
+  if [ ! -f "${NGINX_CONFD}/upstreams.conf" ]; then
+    sudo cp "${SRCDIR}/kiauh/resources/upstreams.conf" "${NGINX_CONFD}"
   fi
-  if [ ! -f "$NGINX_CONFD/common_vars.conf" ]; then
-    sudo cp "${SRCDIR}/kiauh/resources/common_vars.conf" "$NGINX_CONFD"
+  if [ ! -f "${NGINX_CONFD}/common_vars.conf" ]; then
+    sudo cp "${SRCDIR}/kiauh/resources/common_vars.conf" "${NGINX_CONFD}"
   fi
 }
 
@@ -391,15 +404,15 @@ fetch_webui_ports(){
   WEBIFS=(mainsail fluidd octoprint dwc2)
   for interface in "${WEBIFS[@]}"; do
     if [ -f "/etc/nginx/sites-available/${interface}" ]; then
-      port=$(grep -E "listen" "/etc/nginx/sites-available/$interface" | head -1 | sed 's/^\s*//' | sed 's/;$//' | cut -d" " -f2)
-      if [ ! -n "$(grep -E "${interface}_port" "$INI_FILE")" ]; then
-        sed -i '$a'"${interface}_port=${port}" "$INI_FILE"
+      port=$(grep -E "listen" "/etc/nginx/sites-available/${interface}" | head -1 | sed 's/^\s*//' | sed 's/;$//' | cut -d" " -f2)
+      if [ ! -n "$(grep -E "${interface}_port" "${INI_FILE}")" ]; then
+        sed -i '$a'"${interface}_port=${port}" "${INI_FILE}"
       else
-        sed -i "/^${interface}_port/d" "$INI_FILE"
-        sed -i '$a'"${interface}_port=${port}" "$INI_FILE"
+        sed -i "/^${interface}_port/d" "${INI_FILE}"
+        sed -i '$a'"${interface}_port=${port}" "${INI_FILE}"
       fi
     else
-        sed -i "/^${interface}_port/d" "$INI_FILE"
+        sed -i "/^${interface}_port/d" "${INI_FILE}"
     fi
   done
 }
@@ -412,55 +425,55 @@ match_nginx_configs(){
   fluidd_nginx_cfg="/etc/nginx/sites-available/fluidd"
   upstreams_webcams=$(grep -E "mjpgstreamer" /etc/nginx/conf.d/upstreams.conf | wc -l)
   status_msg "Checking validity of NGINX configurations ..."
-  if [ -e "$mainsail_nginx_cfg" ]; then
-    mainsail_webcams=$(grep -E "mjpgstreamer" "$mainsail_nginx_cfg" | wc -l)
+  if [ -e "${mainsail_nginx_cfg}" ]; then
+    mainsail_webcams=$(grep -E "mjpgstreamer" "${mainsail_nginx_cfg}" | wc -l)
   fi
-  if [ -e "$fluidd_nginx_cfg" ]; then
-    fluidd_webcams=$(grep -E "mjpgstreamer" "$fluidd_nginx_cfg" | wc -l)
+  if [ -e "${fluidd_nginx_cfg}" ]; then
+    fluidd_webcams=$(grep -E "mjpgstreamer" "${fluidd_nginx_cfg}" | wc -l)
   fi
   ### check for outdated upstreams.conf
-  if [[ "$upstreams_webcams" -lt "$mainsail_webcams" ]] || [[ "$upstreams_webcams" -lt "$fluidd_webcams" ]]; then
+  if [[ "${upstreams_webcams}" -lt "${mainsail_webcams}" ]] || [[ "${upstreams_webcams}" -lt "${fluidd_webcams}" ]]; then
     status_msg "Outdated upstreams.conf found! Updating ..."
-    sudo rm -f "$NGINX_CONFD/upstreams.conf"
-    sudo rm -f "$NGINX_CONFD/common_vars.conf"
+    sudo rm -f "${NGINX_CONFD}/upstreams.conf"
+    sudo rm -f "${NGINX_CONFD}/common_vars.conf"
     set_upstream_nginx_cfg
     cfg_updated="true"
   fi
   ### check for outdated mainsail config
-  if [ -e "$mainsail_nginx_cfg" ]; then
-    if [[ "$upstreams_webcams" -gt "$mainsail_webcams" ]]; then
+  if [ -e "${mainsail_nginx_cfg}" ]; then
+    if [[ "${upstreams_webcams}" -gt "${mainsail_webcams}" ]]; then
       status_msg "Outdated Mainsail config found! Updating ..."
-      sudo rm -f "$mainsail_nginx_cfg"
-      sudo cp "${SRCDIR}/kiauh/resources/klipper_webui_nginx.cfg" "$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"
+      sudo rm -f "${mainsail_nginx_cfg}"
+      sudo cp "${SRCDIR}/kiauh/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}"
       cfg_updated="true" && ok_msg "Done!"
     fi
   fi
   ### check for outdated fluidd config
-  if [ -e "$fluidd_nginx_cfg" ]; then
-    if [[ "$upstreams_webcams" -gt "$fluidd_webcams" ]]; then
+  if [ -e "${fluidd_nginx_cfg}" ]; then
+    if [[ "${upstreams_webcams}" -gt "${fluidd_webcams}" ]]; then
       status_msg "Outdated Fluidd config found! Updating ..."
-      sudo rm -f "$fluidd_nginx_cfg"
-      sudo cp "${SRCDIR}/kiauh/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"
+      sudo rm -f "${fluidd_nginx_cfg}"
+      sudo cp "${SRCDIR}/kiauh/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}"
       cfg_updated="true" && ok_msg "Done!"
     fi
   fi
   ### only restart nginx if configs were updated
-  if [ "$cfg_updated" == "true" ]; then
+  if [ "${cfg_updated}" == "true" ]; then
     restart_nginx && unset cfg_updated
   fi
 }
 
 process_octoprint_dialog(){
   #ask user to disable octoprint when its service was found
-  if [ "$OCTOPRINT_ENABLED" = "true" ]; then
+  if [ "${OCTOPRINT_ENABLED}" = "true" ]; then
     while true; do
       echo
       top_border
@@ -471,7 +484,7 @@ process_octoprint_dialog(){
       echo -e "|  pected behavior of the Klipper Webinterfaces.        |"
       bottom_border
       read -p "${cyan}###### Do you want to disable OctoPrint now? (Y/n):${default} " yn
-      case "$yn" in
+      case "${yn}" in
         Y|y|Yes|yes|"")
           echo -e "###### > Yes"
           status_msg "Stopping OctoPrint ..."
@@ -492,19 +505,19 @@ process_octoprint_dialog(){
 
 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
@@ -512,19 +525,19 @@ 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
@@ -532,19 +545,19 @@ 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
@@ -554,19 +567,19 @@ process_disruptive_services(){
 
 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 "| ${red}Possibly disruptive/incompatible services found!${default}      |"
       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
@@ -578,7 +591,7 @@ process_services_dialog(){
       echo -e "| ${red}3) Skip this step (not recommended)${default}                   |"
       bottom_border
       read -p "${cyan}###### Please choose:${default} " action
-      case "$action" in
+      case "${action}" in
         1)
           echo -e "###### > Remove packages"
           REMOVE_HAPROXY="true"