Forem: Rafał Sroka

Extracting audio using youtube-dl

Rafał Sroka — Sun, 10 Jul 2022 19:27:11 +0000

Audio could be extracted from a YouTube video using youtube-dl tool.

youtube-dl -x --audio-format mp3 https://www.youtube.com/watch?v=AtPS-pJwBL4

Loading locally created rule configuration to Karabiner

Rafał Sroka — Sat, 09 Apr 2022 17:42:25 +0000

I use a vintage left-handed vertical mouse. It has extra buttons that I have always mapped to Copy and Paste shortcuts to limit moving my hand back to the keyboard.

There were always problems with the mouse driver for macOS. At some point, the driver from Evoluent stopped working whatsoever and I had to look for an alternative. I'd been already using Karabiner to configure custom keyboard mappings so I decided to give it a go and add mappings for the mouse.

In order to create such mappings I had to configure a custom configuration rule and add it to Complex Modifications in the Karabiner preferences.

The following config maps button 4 and button 6 of the mouse to key combos CMD + C and CMD + V.

{
  "title": "Mouse button 4 to copy, button 6 to paste",
  "rules": [
    {
      "description": "Maps mouse button 4 to CMD+C (copy), button 6 to CMD+V (paste).\n",
      "manipulators": [
        {
          "type": "basic",
          "from": {
            "pointing_button": "button4"
          },
          "to": [
            {
              "repeat": false,
              "key_code": "c",
              "modifiers": [
                "left_gui"
              ]
            }
          ]
        },
        {
          "type": "basic",
          "from": {
            "pointing_button": "button6"
          },
          "to": [
            {
              "repeat": false,
              "key_code": "v",
              "modifiers": [
                "left_gui"
              ]
            }
          ]
        }
      ]
    }
  ]
}

Karabiner does not have an easy way of adding custom rules via the UI. There is an UI to import from the Internet or generate rules configuration via online tools.

There is a way to make Karabiner use the locally created rule though. Here's how to do it:

Copy the json file with the rule to ~/.config/karabiner/assets/complex_modifications. Name of the file does not matter. Do it by drag and dropping in Finder or use shell:

cp public/json/rule_configuration.json ~/.config/karabiner/assets/complex_modifications

Import rules from Karabiner-Elements Preferences. Karabiner-Elements Preferences > Complex Modifications > Rules > Add rule

I used Karabiner-Elements version 13.5.0.
The mouse I use is Evoluent Vertical Mouse 4 (left-handed version).

Purge a soft-deleted Azure Key Vault

Rafał Sroka — Sat, 09 Apr 2022 17:35:26 +0000

If you came here you probably already know that delete a Key Vault in Azure is not as easy as it sounds. Sure, it's gone from the Azure portal. However, when you try to create one using the same name you'll find out that it was not fully deleted.

The following recipe shows how to get rid of the Key Vault, for good.

Install Azure CLI according to the following steps. The example below uses homebrew (macOS).
```
brew update && brew install azure-cli
```
Login and find the soft-deleted key vault you want to purge. If you happen to have multiple subscriptions, use the --subscription param to indicate which one should be searched.
```
az login
az keyvault list-deleted
```

Purge it

az keyvault purge --name <keyvault-name>

How to disable security in a PDF that prevents copy & paste

Rafał Sroka — Sat, 09 Apr 2022 17:25:33 +0000

QPDF is a hefty library that can inspect and manipulate the structure of PDF files. It can encrypt and expose the internals of a PDF file, and do many other operations useful to end users and PDF developers.

Some PDF creators enable the read-only mode for their documents. In reality, this way of protection has little sense. It relies on PDF reader apps implementation letting them decide what to do when user tries to copy the text. Many of them show error alerts with a message about disabled copying.

Of course, the text is visible, so nothing prevents us from reading it. The alerts become especially annoying if you own the PDF. You purchased it but since the protection mechanism is still there, you're not allowed to CTRL + C.

The following recipe shows how to solve the problem.

Download QPDF from the official website.
Install it according to the instructions for your OS.
Run

qpdf --decrypt in.pdf out.pdf

How to switch AKS clusters

Rafał Sroka — Sat, 09 Apr 2022 17:13:16 +0000

The following recipe shows how to quickly change the Kubernetes context using Azure CLI.

Step 1. Login to Azure with the Azure CLI

az login

Step 2. Get the list of AKS clusters

az aks list -o table

Step 3. Switch cluster (context)

kubectl config use-context <cluster-name>