Include fix for regex in verifyFreeDiskSpace()

automated install/basic-install.sh

@@ -117,15 +117,19 @@ welcomeDialogs() {
 
 
 verifyFreeDiskSpace() {
-    # 25MB is the minimum space needed (20MB install + 5MB one day of logs.)
-    requiredFreeBytes=25600
-
-    existingFreeBytes=`df -lkP / | awk '{print $4}' | tail -1`
-
-    if [[ $existingFreeBytes -lt $requiredFreeBytes ]]; then
-        whiptail --msgbox --backtitle "Insufficient Disk Space" --title "Insufficient Disk Space" "\nYour system appears to be low on disk space. pi-hole recomends a minimum of $requiredFreeBytes Bytes.\nYou only have $existingFreeBytes Free.\n\nIf this is a new install you may need to expand your disk.\n\nTry running:\n    'sudo raspi-config'\nChoose the 'expand file system option'\n\nAfter rebooting, run this installation again.\n\ncurl -L install.pi-hole.net | bash\n" $r $c
-        exit 1
-    fi
+	# 25MB is the minimum space needed (20MB install + 5MB one day of logs.)
+	requiredFreeBytes=25600
+
+	existingFreeBytes=`df -lk / 2>&1 | awk '{print $4}' | head -2 | tail -1`    	
+	if ! [[ "$existingFreeBytes" =~ ^([0-9])*$ ]]; then       
+		existingFreeBytes=`df -lk /dev 2>&1 | awk '{print $4}' | head -2 | tail -1`		
+	fi
+
+	if [[ $existingFreeBytes -lt $requiredFreeBytes ]]; then        
+		echo "$existingFreeBytes is less than $requiredFreeBytes"
+		echo "Insufficient free space, exiting..."
+		exit 1
+	fi
 }