Consequently use defined file path variables (#4105)

The script defines variables for the most important file paths which are not always used to call the file paths. "lighttpdConfig" was never used in the script itself, so that a shellcheck exception needed to be used. With this change, the defined variables are consequently used, which makes the shellcheck exception obsolete as well.

Additionally the assigned strings are quoted, which is not necessary here but aligns with the coding standard and highlights the strings in most editors and development platforms for developer convenience.

Signed-off-by: MichaIng <micha@dietpi.com>

automated install/basic-install.sh

@@ -47,14 +47,13 @@ EOM
 )
 
 # Location for final installation log storage
-installLogLoc=/etc/pihole/install.log
+installLogLoc="/etc/pihole/install.log"
 # This is an important file as it contains information specific to the machine it's being installed on
-setupVars=/etc/pihole/setupVars.conf
+setupVars="/etc/pihole/setupVars.conf"
 # Pi-hole uses lighttpd as a Web server, and this is the config file for it
-# shellcheck disable=SC2034
-lighttpdConfig=/etc/lighttpd/lighttpd.conf
+lighttpdConfig="/etc/lighttpd/lighttpd.conf"
 # This is a file used for the colorized output
-coltable=/opt/pihole/COL_TABLE
+coltable="/opt/pihole/COL_TABLE"
 
 # Root of the web server
 webroot="/var/www/html"
@@ -1313,18 +1312,18 @@ installConfigs() {
             # make it and set the owners
             install -d -m 755 -o "${USER}" -g root /etc/lighttpd
         # Otherwise, if the config file already exists
-        elif [[ -f "/etc/lighttpd/lighttpd.conf" ]]; then
+        elif [[ -f "${lighttpdConfig}" ]]; then
             # back up the original
-            mv /etc/lighttpd/lighttpd.conf /etc/lighttpd/lighttpd.conf.orig
+            mv "${lighttpdConfig}"{,.orig}
         fi
         # and copy in the config file Pi-hole needs
-        install -D -m 644 -T ${PI_HOLE_LOCAL_REPO}/advanced/${LIGHTTPD_CFG} /etc/lighttpd/lighttpd.conf
+        install -D -m 644 -T ${PI_HOLE_LOCAL_REPO}/advanced/${LIGHTTPD_CFG} "${lighttpdConfig}"
         # Make sure the external.conf file exists, as lighttpd v1.4.50 crashes without it
         touch /etc/lighttpd/external.conf
         chmod 644 /etc/lighttpd/external.conf
         # If there is a custom block page in the html/pihole directory, replace 404 handler in lighttpd config
         if [[ -f "${PI_HOLE_BLOCKPAGE_DIR}/custom.php" ]]; then
-            sed -i 's/^\(server\.error-handler-404\s*=\s*\).*$/\1"pihole\/custom\.php"/' /etc/lighttpd/lighttpd.conf
+            sed -i 's/^\(server\.error-handler-404\s*=\s*\).*$/\1"pihole\/custom\.php"/' "${lighttpdConfig}"
         fi
         # Make the directories if they do not exist and set the owners
         mkdir -p /run/lighttpd
@@ -1892,7 +1891,7 @@ displayFinalMessage() {
     if [[ "${#1}" -gt 0 ]] ; then
         # set the password to the first argument.
         pwstring="$1"
-    elif [[ $(grep 'WEBPASSWORD' -c /etc/pihole/setupVars.conf) -gt 0 ]]; then
+    elif [[ $(grep 'WEBPASSWORD' -c "${setupVars}") -gt 0 ]]; then
         # Else if the password exists from previous setup, we'll load it later
         pwstring="unchanged"
     else
@@ -2550,7 +2549,7 @@ main() {
         # Add password to web UI if there is none
         pw=""
         # If no password is set,
-        if [[ $(grep 'WEBPASSWORD' -c /etc/pihole/setupVars.conf) == 0 ]] ; then
+        if [[ $(grep 'WEBPASSWORD' -c "${setupVars}") == 0 ]] ; then
             # generate a random password
             pw=$(tr -dc _A-Z-a-z-0-9 < /dev/urandom | head -c 8)
             # shellcheck disable=SC1091