Tidying config utils

src/freedombone-utils-config

     param_name="$1"
 
     if [ ${#param_name} -gt 0 ]; then
-        if [ $COMPLETION_FILE ]; then
-            if [ -f $COMPLETION_FILE ]; then
-                if grep -q "${param_name}:" $COMPLETION_FILE; then
-                    param_value=$(cat $COMPLETION_FILE | grep "${param_name}:" | head -n 1 | awk -F ':' '{print $2}')
+        if [ "$COMPLETION_FILE" ]; then
+            if [ -f "$COMPLETION_FILE" ]; then
+                if grep -q "${param_name}:" "$COMPLETION_FILE"; then
+                    param_value=$(grep "${param_name}:" "$COMPLETION_FILE" | head -n 1 | awk -F ':' '{print $2}')
                     echo "$param_value"
                     return
                 fi
     param_name="$1"
     param_value="$2"
 
-    if [ ! $COMPLETION_FILE ]; then
+    if [ ! "$COMPLETION_FILE" ]; then
         COMPLETION_FILE=$HOME/${PROJECT_NAME}-completed.txt
     fi
     if [ ${#COMPLETION_FILE} -eq 0 ]; then
 
     if [ ${#param_name} -gt 0 ]; then
         if [ ${#param_value} -gt 0 ]; then
-            if [ -f $COMPLETION_FILE ]; then
-                if grep -q "${param_name}:" $COMPLETION_FILE; then
-                    sed -i "s|${param_name}:.*|${param_name}:${param_value}|g" $COMPLETION_FILE
+            if [ -f "$COMPLETION_FILE" ]; then
+                if grep -q "${param_name}:" "$COMPLETION_FILE"; then
+                    sed -i "s|${param_name}:.*|${param_name}:${param_value}|g" "$COMPLETION_FILE"
                 else
-                    echo "${param_name}:${param_value}" >> $COMPLETION_FILE
+                    echo "${param_name}:${param_value}" >> "$COMPLETION_FILE"
                 fi
             else
-                echo "${param_name}:${param_value}" > $COMPLETION_FILE
+                echo "${param_name}:${param_value}" > "$COMPLETION_FILE"
             fi
         fi
     fi
 function mark_completed {
     param_name="$1"
 
-    if [ ! $COMPLETION_FILE ]; then
+    if [ ! "$COMPLETION_FILE" ]; then
         COMPLETION_FILE=$HOME/${PROJECT_NAME}-completed.txt
     fi
     if [ ${#COMPLETION_FILE} -eq 0 ]; then
     fi
 
     if [ ${#param_name} -gt 0 ]; then
-        if [ -f $COMPLETION_FILE ]; then
-            if ! grep -Fxq "${param_name}" $COMPLETION_FILE; then
-                echo "${param_name}" >> $COMPLETION_FILE
+        if [ -f "$COMPLETION_FILE" ]; then
+            if ! grep -Fxq "${param_name}" "$COMPLETION_FILE"; then
+                echo "${param_name}" >> "$COMPLETION_FILE"
             fi
         else
-            echo "${param_name}" > $COMPLETION_FILE
+            echo "${param_name}" > "$COMPLETION_FILE"
         fi
     fi
 }
 function is_completed {
     param_name="$1"
 
-    if [ ! $COMPLETION_FILE ]; then
-        COMPLETION_FILE=$HOME/${PROJECT_NAME}-completed.txt
+    if [ ! "$COMPLETION_FILE" ]; then
+        COMPLETION_FILE="$HOME/${PROJECT_NAME}-completed.txt"
     fi
     if [ ${#COMPLETION_FILE} -eq 0 ]; then
-        COMPLETION_FILE=$HOME/${PROJECT_NAME}-completed.txt
+        COMPLETION_FILE="$HOME/${PROJECT_NAME}-completed.txt"
     fi
 
     if [ ${#param_name} -gt 0 ]; then
-        if [ -f $COMPLETION_FILE ]; then
-            if grep -Fxq "${param_name}" $COMPLETION_FILE; then
+        if [ -f "$COMPLETION_FILE" ]; then
+            if grep -Fxq "${param_name}" "$COMPLETION_FILE"; then
                 echo "1"
                 return
             fi
     param_name="$1"
 
     if [ ${#param_name} -gt 0 ]; then
-        if [ $CONFIGURATION_FILE ]; then
-            if [ -f $CONFIGURATION_FILE ]; then
-                if grep -q "${param_name}=" $CONFIGURATION_FILE; then
-                    param_value=$(cat $CONFIGURATION_FILE | grep "${param_name}=" | head -n 1 | awk -F '=' '{print $2}')
-                    if [[ "${param_value}" != *" "* ]]; then
-                        export ${param_name}=${param_value}
-                    else
-                        export ${param_name}="${param_value}"
-                    fi
+        if [ "$CONFIGURATION_FILE" ]; then
+            if [ -f "$CONFIGURATION_FILE" ]; then
+                if grep -q "${param_name}=" "$CONFIGURATION_FILE"; then
+                    param_value=$(grep "${param_name}=" "$CONFIGURATION_FILE" | head -n 1 | awk -F '=' '{print $2}')
+                    export "${param_name}"="${param_value}"
                 fi
             fi
         fi
     param_name="$1"
 
     if [ ${#param_name} -gt 0 ]; then
-        if [ $CONFIGURATION_FILE ]; then
-            if [ -f $CONFIGURATION_FILE ]; then
-                if grep -q "${param_name}=" $CONFIGURATION_FILE; then
-                    param_value=$(cat $CONFIGURATION_FILE | grep "${param_name}=" | head -n 1 | awk -F '=' '{print $2}')
+        if [ "$CONFIGURATION_FILE" ]; then
+            if [ -f "$CONFIGURATION_FILE" ]; then
+                if grep -q "${param_name}=" "$CONFIGURATION_FILE"; then
+                    param_value=$(grep "${param_name}=" "$CONFIGURATION_FILE" | head -n 1 | awk -F '=' '{print $2}')
                     if [ ${#param_value} -gt 0 ]; then
                         echo "1"
                         return
     param_name="$1"
     param_value="$2"
 
-    if [ ! $CONFIGURATION_FILE ]; then
+    if [ ! "$CONFIGURATION_FILE" ]; then
         CONFIGURATION_FILE=$HOME/${PROJECT_NAME}.cfg
     fi
     if [ ${#CONFIGURATION_FILE} -eq 0 ]; then
 
     if [ ${#param_name} -gt 0 ]; then
         if [ ${#param_value} -gt 0 ]; then
-            if [ -f $CONFIGURATION_FILE ]; then
-                if grep -q "${param_name}=" $CONFIGURATION_FILE; then
-                    sed -i "s|${param_name}=.*|${param_name}=${param_value}|g" $CONFIGURATION_FILE
+            if [ -f "$CONFIGURATION_FILE" ]; then
+                if grep -q "${param_name}=" "$CONFIGURATION_FILE"; then
+                    sed -i "s|${param_name}=.*|${param_name}=${param_value}|g" "$CONFIGURATION_FILE"
                 else
-                    echo "${param_name}=${param_value}" >> $CONFIGURATION_FILE
+                    echo "${param_name}=${param_value}" >> "$CONFIGURATION_FILE"
                 fi
             else
-                echo "${param_name}=${param_value}" > $CONFIGURATION_FILE
+                echo "${param_name}=${param_value}" > "$CONFIGURATION_FILE"
             fi
         fi
     fi
     param_name="$1"
 
     if [ ${#param_name} -gt 0 ]; then
-        if [ $CONFIGURATION_FILE ]; then
-            if [ -f $CONFIGURATION_FILE ]; then
-                if grep -q "${param_name}=" $CONFIGURATION_FILE; then
-                    sed -i "/${param_name}=/d" $CONFIGURATION_FILE
+        if [ "$CONFIGURATION_FILE" ]; then
+            if [ -f "$CONFIGURATION_FILE" ]; then
+                if grep -q "${param_name}=" "$CONFIGURATION_FILE"; then
+                    sed -i "/${param_name}=/d" "$CONFIGURATION_FILE"
                 fi
             fi
         fi
     param_name="$1"
 
     if [ ${#param_name} -gt 0 ]; then
-        if [ $COMPLETION_FILE ]; then
-            if [ -f $COMPLETION_FILE ]; then
-                if grep -Fxq "${param_name}" $COMPLETION_FILE; then
-                    sed -i "/${param_name}/d" $COMPLETION_FILE
+        if [ "$COMPLETION_FILE" ]; then
+            if [ -f "$COMPLETION_FILE" ]; then
+                if grep -Fxq "${param_name}" "$COMPLETION_FILE"; then
+                    sed -i "/${param_name}/d" "$COMPLETION_FILE"
                 fi
-                if grep -q "${param_name}:" $COMPLETION_FILE; then
-                    sed -i "/${param_name}:/d" $COMPLETION_FILE
+                if grep -q "${param_name}:" "$COMPLETION_FILE"; then
+                    sed -i "/${param_name}:/d" "$COMPLETION_FILE"
                 fi
             fi
         fi
 
 function read_configuration_values {
     # if not installing on a Beaglebone then use sdb as the USB drive by default
-    if [ ! $INSTALLING_ON_BBB ]; then
+    if [ ! "$INSTALLING_ON_BBB" ]; then
         if [[ $USB_DRIVE == /dev/sda1 ]]; then
             USB_DRIVE=/dev/sdb1
         fi
     fi
 
-    if [ -f $CONFIGURATION_FILE ]; then
+    if [ -f "$CONFIGURATION_FILE" ]; then
         # Ensure that a copy of the config exists for upgrade purposes
         if [[ $CONFIGURATION_FILE != "/root/${PROJECT_NAME}.cfg" ]]; then
-            cp $CONFIGURATION_FILE /root/${PROJECT_NAME}.cfg
+            cp "$CONFIGURATION_FILE" "/root/${PROJECT_NAME}.cfg"
         fi
 
         for v in "${configuration_variables[@]}"
             read_config_param "$v"
         done
 
-        if grep -q "DEBIAN_REPO" $CONFIGURATION_FILE; then
+        if grep -q "DEBIAN_REPO" "$CONFIGURATION_FILE"; then
             read_config_param "DEBIAN_REPO"
+            # shellcheck disable=SC2034
             CHECK_MESSAGE=$"Check your internet connection, /etc/network/interfaces and /etc/resolvconf/resolv.conf.d/head, then delete $COMPLETION_FILE, run 'rm -fR /var/lib/apt/lists/* && apt-get update --fix-missing' and run this script again. If hash sum mismatches persist then try setting $DEBIAN_REPO to a different mirror and also change /etc/apt/sources.list."
         fi
     fi
 
 function read_configuration {
     if [[ $INSTALLING_FROM_CONFIGURATION_FILE == "yes"  ]]; then
-        if [ ! -f $CONFIGURATION_FILE ]; then
+        if [ ! -f "$CONFIGURATION_FILE" ]; then
             echo $"The configuration file $CONFIGURATION_FILE was not found"
             exit 8935
         fi
 
 # check that domain names are valid and that they are unique for each app
 function check_domains {
-    specified_domains=$(cat $CONFIGURATION_FILE | grep "_DOMAIN_NAME" | uniq)
-    domains_array=($specified_domains)
+    specified_domains=$(grep "_DOMAIN_NAME" "$CONFIGURATION_FILE" | uniq)
+    domains_array=("$specified_domains")
     checked_domains=()
 
     for d in "${domains_array[@]}"
         if [[ "$domain_param" != "DEFAULT_DOMAIN_NAME" ]]; then
             domain_value=$(echo "$d" | awk -F '=' '{print $2}')
             if [[ "$domain_value" != "${LOCAL_NAME}.local" ]]; then
-                item_in_array "${domain_value}" "${checked_domains[@]}"
-                if [[ $? != 0 ]]; then
+                if ! item_in_array "${domain_value}" "${checked_domains[@]}"; then
                     # test that this is a valid domain name
                     function_check test_domain_name
                     test_domain_name "$domain_value"