URL Rewrite in nginx (coming from Apache)

If you are like me, you already know how to use MOD-REWRITE in apache2, but need guidance to implement things in nginx !

There are three directives in nginx concerning rewriting, namely return, rewrite, and try_files Directives, what i will be starting with is rewrite, since most websites on Apache use “rewrite_rule” which can be easily translated into rewrite

I will also provide the most common examples for software such as WordPress, laravel, and other software so that you can get up and running in the shortest possible time

1- Translating my RewriteRule from Apache into nginx

The good news is, it is very easy, I will provide a few simple guidelines, then provide examples.

  • The counterpart to RewriteRule in apache2 in nginx is rewrite, so start by changing the text RewriteRule into rewrite
  • Replace [L] or [QSA,L] with the string “last;”, Notice that configuration entries in nginx end in a semicolon
  • Wherever there is an occurrence of ^ follow it with a /, Making it ^/
  • In nginx, curly braces are used for two purposes, block control and regular expressions, so if your existing apache2 rules contain those curly braces for regular expressions, you can tell nginx that this is a regular expression not block control by surrounding the regular expression with quotes (double or single).

So let me create an example, explain what it does, and show you how it is translated into nginx rewrite

What it doesIn ApacheIn nginx
This rewrites
everything onto
the index.php file,
except for the
contents of one
folder named
* RewriteEngine on
* RewriteRule ^norewrite(.) – [L]
* RewriteRule ^(.)$ index.php?q=$1 [L,QSA]
Create a separate section
for the folder norewrite,
and then use the following
* rewrite ^(.*)$ /index.php?q=$1 last;

Changing the default port 80 on nginx

First of all, check what ports nginx is currently using, you can do that with any of the following commands

netstat -tlpn| grep nginx
ss -tlpn| grep nginx

So, you probably found nginx listening to port 443 for SSL connections, and on port 80 for plain http….

On many occasions, you may want other application (Such as varnish or apache) to be listening on port 80, So nginx needs to move to another port, in this example, I am moving it to port 8080

Step 1: Go to sites available, there is the default site, and there are any other sites you added to nginX, open those config files that you will find in /etc/nginx/sites-available, search for 80, and replace it wherever it may occure with 8080 or any port of your choice, restrictions are the following, port numbers under 1024 will requier root privilages (So keep it above 1024), and the maximum port number is 65535, Also port 0 can not be used for http (Relevant to UDP though)

Will changing my transmission fluid break it

So i have a 2008 Mercedes-Benz E 200 Kompressor 5G-Tronic. being aware of the theory that changing transmission fluid after having 135K Kms on the car will break my transmission/gearbox and finding it hard to believe, I decided to try it myself.

Why I am doubting this theory

My theory is about the origins of “transmissions break when fluid is changed”, and why it is likely WRONG.

The origin of that theory is probably the number of people who have problems soon after changing transmission fluid, and basically there is nothing wrong with the theory in this regard but bear with me.

my counter theory is, when people change their transmission fluid at such high mileage, they are not exactly servicing the car on proper intervals, the reminder to change the fluid for them was probably that the transmission acting up, so the transmission is on it’s last leg, you change the fluid, but the fluid can’t save the transmission, it is too late, the dirt in the dirty transmission fluid was creating a bit of friction (and accelerating the wear in the process), the situation is bad enough that you went to change the fluid to see if that helps, the transmission keeps on deteriorating because it is already going in that direction, so what do you do, you blame the oil change ! “It was working at least before I changed the oil !”

So my car comes with the 1.8L M271 , My transmission is probably the 722.695.

I have already drained 3Liters of fluid (All that was in the pan), and filled the transmission with 3 liters of Mercedes-Benz 236.14 transmission fluid, I have also replaced the oil filter and the pan gasket. there is a magnet stuck to the pan from the inside, be sure to clean that too !

Later on, I drained another liter and a half, and added a liter and a half, and kept half a liter to top it up once i find my relevant dipstick (Does not come with the car)

There are alternatives to the somewhat expensive MB fluid, but since i couldn’t find an MB certified one, or at least a fluid that claims to be the same, I decided to bite the bullet and go with the original.

Repairing the Prius HV traction battery

Attention: the stuff/information you need is at the beginning, Most of the stuff that follow the practical section you will not need (The some theory section), whatever more you see is for my reference, for the curious, and for those who are wondering why i do it this way.

The lowdown: I have successfully repaired my 2014 (3rd gen) Prius battery, despite the fact that most information on rebuilding your Prius battery online is Bull, almost as if it were engineered so that you kill the remaining good cells after a month or two.

this is going to be one long article, and probably a video will follow.

Here are the tools you need

  • An android phone (You can use Apple/iPhone with torque pro, but the instructions here are for android)
  • The Torque Pro app on the phone
  • Prius PIDs for torque pro (Download here)
  • A compatible OBD2 adapter, I use a WiFi adapter, you can use a Bluetooth or any other that works with torque pro
  • A laptop with software like excel or LibreOffice calc, A paper and pen should also work
  • A charger capable of charging a battery of 6 NIMH cells (Battery means in series), I use the SKYRC imax B6 mini
  • Car headlight lamps (To drain the batteries)

Like everyone else, it all started with CHECK HYBRID SYSTEM STOP THE VEHICLE IN A SAFE PLACE getting displayed on my center “multi information display / instrument panel” or MID for short.

Connecting the OBD2 adapter resulted in fault code (P0a80) other relevant codes might display with P0a80 such as p3011, p3012, p3013 etc. which should point you to the failing module pairs that are causing the failure. in my case, I only had the P0a80.

Prius battery terminology (As per Toyota)

Hybrid battery: the whole Prius traction battery pack of 28 modules
Module Pair: the car reads voltages of modules in pairs, So voltages of the 28 modules in a Prius battery are reported to the car as 14 values, meaning every 2 modules are read together as the sum of the voltage of those 2 modules.
Battery Module: in a Prius battery, every 6 cells are enclosed in a sealed container called a module, this is why you don’t directly see the cells, a module’s nominal voltage is 7.2, which is the nominal voltage of 1 cell multiplied by 6.
Battery Cell: A 1.2V NIMH cell that you will not see because it is hidden inside a module.

So, without further ado, let us get started

Diagnosis, which modules are bad

Before we take the battery out, we can save a hell lot of time by looking at what the car has to say about it’s battery pack.

I have broken this down to steps you see below

  • Install torque pro to your phone (android in my case)
  • Download the Prius 3rd Gen PIDs file by clicking here
  • extract the file you have just downloaded to the (/.torque/extendedpids) directory in your phone
  • Open torque pro, and go to the Menu -> Settings -> Manage extra PIDs/Sensors -> Menu -> Add predefined set.
  • Create an Realtime Information page in torque pro to display battery voltages in real time such as the one below, you start with an empty page, then add (tiny) displays corresponding to voltages of individual modules, I personally like to add the Min and Max voltage entries to make it easier to know when you have found what you are looking for while driving without having to scan through the batteries
  • Clear the error code, switch the car off then on again, the car should now appear to be working fine as if the battery is okay, this is obviously just for the test as the car will soon find out the problem again and inform you of your problem
  • Now, once connected and information is displayed, find a nice uphill climb that is not too steep, with no traffic, at the bottom of that climb, floor the break and gas pedal at the same time, this will charge the battery, then on EV, start climbing wile recording your phone screen, the battery should drain really fast and you will either hear the engine running, or the “Check hybrid system” message should appear again, either way, you now have a reading of which batteries drained very fast…
  • Inspect the recorded screen recording, and figure out which modules are the ones causing the problem, please note that there may be other modules in bad shape, but for now, the worst ones are clear

Taking the battery out of the car

To be able to pull the battery out of the car, you will need to take the following steps

Some theory

The 20% to 80%

Q: Why does the car consider the battery fully charged at 80%, and depleted at 20% of the batteries actual capacity ?

A- Why the 80% cap ?

Let us start with why it caps at 80% ! (At 80 percent, 100% will display on your instrument cluster)

The most common theory (that i don’t find convincing) is that the car wants to leave headroom for regenerative breaking, if it were so, why does it start using the gas engine’s breaking at 80% ? burning fuel, and defeating the purpose of regenerative breaking ?

My own theory is that there are multiple reasons, of which the headroom theory above is not one… here are the reasons i expect the car was designed this way

1- NIMH batteries heat up once you are charging above 80%, which is wasted energy, so the car is expected to try an use up the battery back down to the happy 6/8 area.
2- Heat is bad for the module’s health, and the health of the modules around it (See 1)
3- When modules in module pairs become mismatched health wise, this 20% headroom spares the weaker cell the overcharge and the damage associated with it., illustration will be added soon.

B- And the 20% depletion mark ?
NIMH cells can be depleted to ZERO, in fact, the company that makes the enelope batteries for Panasonic calls depleting the battery to zero and then charging it again a refresh function.

The area between 0.9V and zero volts has very little energy, as most energy is delivered between 1.3 and 1 volt, but still, this area is much less than 20% ! so why 20%

1- Unlike gas cars, hybrid vehicles do not have a 12V starter motor, the gas engine in a hybrid car is started by the electric motor itself, the same one used to propel the car is used to start the engine, if the battery falls below 20%, especially as batteries start to age, there will not be enough power to start the engine, more to that, the batteries have internal resistance, so the car needs to be sure that when it is parked for a few days (or months), it will have enough traction battery power to start the gas engine.

Creating images with AI (Programming)

So, I will start by dropping a few keywords here, and what they are about, that will probably help you start, I am compiling this as a guideline on where to start

  • VQGAN (Vector Quantized Generative Adversarial Network / neural network) : The software that generates the image
  • CLIP (Contrastive Language-Image Pre-training / neural network) : Software to influence a generated image based on input text (User prompt)
  • VQGAN+CLIP : Two neural network pieces of software that work in tandem.
  • CLIP-Guided-Diffusion: A technique for doing text-to-image synthesis cheaply using pre-trained CLIP and diffusion models.
  • Google colab notebook: A tool made by google where you can run python code and utilize google’s GPUs, both paid and free exist

The best Bluetooth transmitter (And receiver)

I am writing a post about this device because I was positively surprised by it

I have a TV connected to an android TV box, neither the TV nor the android box have bluetooth, So i have tried quite a few bluetooth transmitters, where you connect the AUX jack from the TV out to the transmitter, and the transmitter automatically pairs with the bluetooth speakers, never went well, either the voice is really bad, or it does not work, this is all until i found this little cool guy

So, how those transmitters usually work is you power the thing from USB, then connect the auxiliary jack, to my surprise, even though this did have a 3.5MM aux jack, it was detected by my android box as a USB sound card, and it worked without me doing anything

It doubles as a BT receiver too, but those are all over the place, and not exactly why i like this, So now it is clear what they mean by 3IN1, it has a jack for input, output and also works as USB sound ! Amazing stuff

Tunneling Firefox traffic through SSH – Putty

I will here assume you already have a remote Linux machine that you can SSH into with putty, the instructions are simple from this point on

Putty Setup

1- Basic putty settings, assuming you have already downloaded putty from chiark.greenend.org.uk, now open putty, enter the IP of the server you wish to tunnel through, and save it with a name, the steps are…
– Open putty,
– enter the IP of your remote machine
– give it a name of your choice
– save (You don’t need to save now, you will save again in a bit, but you can do it anyway)

2- Go to Connection and expand it, then expand SSH, then select Tunnels, this will show a dialogue such as the below, fill in the data as follows

  • A Source port between 1025-65536 (of your choice), i chose 8081 but you can chose any other in that range
  • Check Dynamic and Auto, the click Add

3- From the menu on the left, go back to Session, and click the save button again (So that the new tunnel settings are saved for next time)

4- You are almost done, Now double click the saved session name or select it and hit open, the remote machine should now prompt you to enter a username and a password, once you enter those, you have a tunnel ready on your localhost ( on port 8081, next we will setup Firefox to use that tunnel

Firefox setup

1- Go to firefox settings (Click the accordion menu to the right, and chose settings), once open, scroll down under general, until you find the Network Settings section, click the settings button in that section

Clicking settings above will show the following popup dialogue, setup your system as follows

  • Manual Proxy Configuration
  • SOCKS Host enter and in the port area of that the port we chose in putty (In my case, 8081)
  • Optional – Add the IP address ranges of the IPs that you do not want to have tunneled through the remote machine
  • For more privacy, and sometimes functionality (When access is blocked from abroad), make sure you tunnel your DNS queries as well (See checkbox below)

Now, to verify that you are conencted to the remote machine, google the following

what is my ip

and google should tell you what your IP address is, at this stage, it should be the same as the remote machine’s IP (Not yours)

Free SSL certificates with Let’s encrypt, step by step

Let’s encrypt is a Certificate Authority (CA) run by Internet Security Research Group (ISRG), and is sponsored by some of the biggest name in the web industry

You are probably here to create a certificate, not get a history lesson ! so Let me cut the chase, for those who want to know more, there is always wikipedia (Let’s encrypt on Wikipedia)

So let’s encrypt provides certificates for domain names, including wildcard certificates (Which I will get to by the end of this article), What we are going through here is the manual process, which serves to give you a taste of how things work, in practice, you are encouraged to use on of the automated methods for multiple reasons, one compelling such reason is that Let’s encrypt issues certificates valid for three months only ! You don’t want to have to cater to your certificate every three months do you ?

To simplify things, I will create a step by step video to demonstrate the creation process ! and post it here, but for now, I will simply take you through the steps, in this tutorial, all you need is SSH access to any server including one you have at home ! or even maybe a virtual machine running Linux inside your windows computer, anything goes, once you have a certificate, you can move it to your production server, this allows me to keep this as general as possible, and this is done using the –manual option, So without further ado, let me get to it

1- login to a linux server and install certbot, the tool that allows you to get certificates from let’s encrypt, On the official website, they promote the use of SNAP, here, I will skip snap and use Debian’s repository ! simpler and there is no need to get into snap

apt install certbot

Now that you have certbot, let us create a certificate for the domain example.com (replace it with your own)

certbot certonly --manual --preferred-challenges http

The –preferred-challenges directive allows you to specify what challenge (http or dns) you would like to perform, the manual plugin is basically the same as webroot plugin but not automated, which is a hassle to keep up to date as this form of issuance needs to be renewed manually every 3 months, (You can take extra steps to automate this) which i will describe later on another post to keep things tidy

Now, as soon as you enter the above, you will enter an interactive dialogue with the following steps

Note: If you want to create a wildcard certificate for your domain name, let’s encrypt allows the use of the * wildcard, but only supports DNS challenge, so the command must reflect that, So when asked for a domain, simply enter *.example.com (or -d ‘*.example.com’), should work normally

As soon as you are in, you will be asked

1- An email for notifications
2- Do you agree to the terms of service ?
3- Would you like to subscribe to the newsletter ?
4- enter your domain names (you should enter both example.com and www.example.com separated by either a comma or a space)

Create a file containing just this data:


And make it available on your web server at this URL:


6- Now you need to create the 2 challenge files, one for exmaple.com and the other for WWW.example.com

Create a file containing just this data:


And make it available on your web server at this URL:


(This must be set up in addition to the previous challenges; do not remove,
replace, or undo the previous challenge tasks yet.)


 - Congratulations! Your certificate and chain have been saved at:
   Your key file has been saved at:
   Your certificate will expire on 2023-03-11. To obtain a new or
   tweaked version of this certificate in the future, simply run
   certbot again. To non-interactively renew *all* of your
   certificates, run "certbot renew"
 - If you like Certbot, please consider supporting our work by:

   Donating to ISRG / Let's Encrypt:   https://letsencrypt.org/donate
   Donating to EFF:                    https://eff.org/donate-le

At this stage, there are things you should remain aware of

1- DO NOT RENAME OR MOVE THE CERTIFICATES, they need to be in place for renewal if you decide to not automate and check on your certificates every 3 months.

2- Copy (Don’t move) them to the ssl directory, and add them to your config files, the only files you will need to include in your nginx or apache2 config are as follows

For apache 2, you need to use the following 2 lines, modify the path to the files to wherever you have placed them

      SSLCertificateFile /etc/apache2/ssl/example.com/fullchain.pem
      SSLCertificateKeyFile /etc/apache2/ssl/example.com/privkey.key

And for nginx

        ssl_certificate /etc/nginx/ssl/allspots.com/fullchain.pem;
        ssl_certificate_key /etc/nginx/ssl/allspots.com/privkey.pem;

So, restart apache or nginx, and you should be able to see the certificate in action, so this is the simplest way to use let’s encrypt, in my next post, I will

Now, after 3 months, the simplest way to renew the certificate is to issue the command

certbot certonly --force-renew -d example.com www.example.com