1030Concatenating Videos with ffmpeg

Concatenating videos with the Quicktime Player requires unnecessary decoding/encoding, with takes time and computational resources.


Using ffmpeg

  1. Create a list: mylist.txt

    file '/path/to/file1.mp4'
    file '/path/to/file2.mp4'
    file '/path/to/file3.mp4'
  2. Run ffmpeg `ffmpeg -f concat-i mylist.txt -c copy output.mp4

1028Setting up GitHub Command-Line Access

This is a short, condensed instruction how to set-up command-line access to github.com. Written is response to onboard new FabAcademy students - and get them started with MkDocs.

This guides is for macOS 12 or higher. My Mac uses macOS Ventura 13.0.01.

Step 1: Creating a new SSH Key

Go to the .ssh directory.

$ cd ~/.ssh

Made new key:

$ ssh-keygen -t ed25519 -C "your_email@example.com"
  • Don't just copy, put in your email. I also added a password.
  • Also, don't copy the $, just the ssh-keygen -t ed25519 -C "your_email@example.com" part. But with your email.

You can name your key. For this example, we call it id_github_test.

Step 2: Adding SSH Key to ssh-agent.

$ eval "$(ssh-agent -s)"

Step 3: Adding Key Info to config

Open .ssh/config in your favourite text editor. If you want to stay at the command line, use nano.

Add the following:

Host *.github.com
  AddKeysToAgent yes
  UseKeychain yes
  IdentityFile ~/.ssh/id_github_test

Step 4: Adding the Key to ssh-agent

Adding private key to ssh-agent

$ ssh-add --apple-use-keychain ~/.ssh/id_github_test

This add the new key to the Apple Keychain.

If you used a passphrase when you created the key, you will be asked for it now.

Enter passphrase for /Users/georg/.ssh/id_github_test: 
Identity added: /Users/georg/.ssh/id_github_test (your_email@example.com)

Step 5: Adding Public Key to github.com

  • Log into Github
  • Profile > Settings > SSH and GPG Keys
  • Click 'New SSH Key'

Copy and paster your public key, in this example case, id_github_test.pub.

The tutorial on Github suggest to copy the public key using a command:

$ pbcopy < ~/.ssh/id_github_test.pub      

pbcopy - for paste board copy is the terminal interface to the macOS' Copy & Paste. pbcopy < read the content of a file into the copy memory. After running pbcopy you can press Command-V to paste the text.

  • Paste the copied SSH Public Key.

Step 5.1: Two-Factor Authentication at GitHub.com

I setup Two-Factor Authentication at GitHub.com, I had to confirm the addition of a new key via my mobile GitHub App. Your mileage might vary.

Step 6: Testing the connection

$ ssh -T git@github.com
Hi trembl! You've successfully authenticated, 
but GitHub does not provide shell access.

Ok, great! It worked!

Now you can clone, add, commit, push and pull!


1027SSH Key Permissions too open

This warning is pretty self- explanatory:

Permissions 0644 for '/Users/georg/.ssh/my_rsa_key' are too open.
It is required that your private key files are NOT accessible by others.
This private key will be ignored.


Limit the key to read/write access by the user only:

chmod 600 ~/.ssh/my_rsa_key

It's also possible to make it only readable by the user, but then you need to chmod every time you want to update/change it.

chmod 400 ~/.ssh/my_rsa_key

Sources: StackOverflow

1025hugo Shortcuts

Quick run through hugo Installation & Update on macOS.

Install hugo

brew install hugo

Check Version

hugo version

hugo v0.109.0+extended darwin/amd64 BuildDate=unknown

Upgrade hugo

brew upgrade hugo
Warning: hugo 0.109.0 already installed

Create New Site

hugo new site my-new-hugo-site
cd my-new-hugo-site
git init
git submodule add https://github.com/theNewDynamic/gohugo-theme-ananke themes/ananke
echo "theme = 'ananke'" >> config.toml

hugo does not come with an in-built theme, therefore we need to clone the anake theme into themes/ananke. More hugo themes. Clone and update config.toml.

Serve Site

hugo server

Build Site

Just hugo, nothing else.

Start building sites … 
hugo v0.109.0+extended darwin/amd64 BuildDate=unknown
INFO 2022/12/26 19:37:15 syncing static files to /

                   | EN  
  Pages            | 10  
  Paginator pages  |  0  
  Non-page files   |  0  
  Static files     |  1  
  Processed images |  0  
  Aliases          |  1  
  Sitemaps         |  1  
  Cleaned          |  0  

Total in 154 ms

1024mkDocs Shortcuts

Quick run through mkDocs Installation & Update on macOS.

Install mkDocs

pip install mkdocs

Check Version

mkdocs -V

mkdocs, version 1.1.2 from /usr/local/lib/python3.9/site-packages/mkdocs (Python 3.9)

Update mkDocs

pip install -U mkdocs
mkdocs -V

mkdocs, version 1.4.2 from /usr/local/lib/python3.9/site-packages/mkdocs (Python 3.9)

Install mkdocs-material

pip install mkdocs-material

Update to latest mkdocs-material

pip install -U mkdocs-material

Create new mkDocs Site

mkdocs new my-new-site

Start Serving Site

cd my-new-site
mkdocs serve

Stop Serving Site

⌨️: ^[ctrl]-C

1021Facebook Custom Share Link

Facebook's depreciate Custom Share Link (as of 2022). Still work, but not recommended.


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1019Importing Screenshots to Photos with Automator

A simple Automator Action to import Screenshots in OSX into Photos:

  • Select the Folder to which the Action is attached
  • "Add to existing top-level album" - called "Screenshots"

I also have my Screenshots Folder on Dropbox, the Folder Actions are attached to that Folder.

1017Finding and Deleting Files without Content

Finds all empty JPEGs at current directory:

find . -maxdepth 1 -name "*.jpg" -size 0

Finds and deletes all empty JPEGs at current directory:

find . -maxdepth 1 -name "*.jpg" -size 0 -delete

Finds and deletes all empty JPEGs in all sub-directories.

find . -maxdepth 2 -name "*.jpg" -size 0 -delete

Sources: 1, 2

1014Installing IIJmio Sim-Card on iPhone

Problem: IIJMIO Network not working: Solution: Dowload and Install Profile 1. Go to https://t.iijmio.jp/en/apn/ 2. Download and Install the Profile 3. That’s it.

1010Importing MySQL dump file into Database

Working with XAMPP and and phpMyAdmin makes dealing with databases more visual, but importing large db dumb files can fail/take a long time.

Importing from the command line is faster and more stable.

Use the XAMPP mysql, if there is not a global mysql

cd /Applications/XAMPP/xamppfiles/bin 


./mysql -u root -p db_name < ~/path/to/db/file.sql
  • Importing a ca. 300MB file takes ca. 5 seconds.
  • Make sure the DB "db_name" already exists.