refactored cf_ufw.sh

- Added double quotes to variable expansions to prevent word splitting and pathname expansion.
- Used "$()" for command substitution instead of using backticks, as it's the recommended way.
- Used printf instead of echo for printing to the console.
Simplified the way to append a newline to the temporary file.

cf_ufw.sh

@@ -15,48 +15,45 @@ RULE_COMMENT="Cloudflare"
 
 # Check if the required tools are installed
 check_dependencies() {
-  if ! command -v ufw > /dev/null; then
-    echo "UFW is not installed. Aborting."
-    exit 1
-  fi
-
-  if ! command -v curl > /dev/null; then
-    echo "curl is not installed. Aborting."
-    exit 1
-  fi
+  for cmd in ufw curl; do
+    if ! command -v "$cmd" > /dev/null; then
+      printf "Command not found in PATH: %s\n" "$cmd"
+      exit 1
+    fi
+  done
 }
 
 # Check if the user has sufficient permissions
 check_permissions() {
   if [ "$(id -u)" -ne 0 ]; then
-    echo "This script must be run as root. Aborting."
+    printf "This script must be run as root. Aborting.\n"
     exit 1
   fi
 }
 
 # Fetch the latest Cloudflare IP ranges and update UFW rules accordingly
 fetch_and_update_ranges() {
   # Retrieve the latest IPv4 and IPv6 IP ranges from Cloudflare.
-  if ! curl -s --retry 3 --retry-delay 5 "$CLOUDFLARE_IPv4_URL" -o "$TEMP_FILE"; then
-    echo "Failed to fetch IPv4 addresses. Aborting."
+  if ! curl -s --retry 3 --retry-delay 5 "${CLOUDFLARE_IPv4_URL}" -o "${TEMP_FILE}"; then
+    printf "Failed to fetch IPv4 addresses. Aborting.\n"
     exit 1
   fi
 
-  echo "" >> "$TEMP_FILE"
+  printf "\n" >> "${TEMP_FILE}"
 
-  if ! curl -s --retry 3 --retry-delay 5 "$CLOUDFLARE_IPv6_URL" >> "$TEMP_FILE"; then
-    echo "Failed to fetch IPv6 addresses. Aborting."
+  if ! curl -s --retry 3 --retry-delay 5 "${CLOUDFLARE_IPv6_URL}" >> "${TEMP_FILE}"; then
+    printf "Failed to fetch IPv6 addresses. Aborting.\n"
     exit 1
   fi
 
   # Update UFW rules to allow traffic only on ports 80 (TCP) and 443 (TCP) from the fetched IP ranges.
   # If a rule for a specific subnet already exists, UFW will not create a duplicate rule.
   while IFS= read -r ip; do
-    ufw allow from "$ip" to any port "$ALLOWED_PORTS" proto tcp comment "$RULE_COMMENT"
-  done < "$TEMP_FILE"
+    ufw allow from "${ip}" to any port "${ALLOWED_PORTS}" proto tcp comment "${RULE_COMMENT}"
+  done < "${TEMP_FILE}"
 
   # Remove the temporary file containing the IP ranges.
-  rm "$TEMP_FILE"
+  rm "${TEMP_FILE}"
 }
 
 # Main function to run the script