Friedrich Ewald · My Personal Website

Mass remove git branches

Dec 2, 2025 · 1 min read

To mass remove git branches from a git repository, you can use the following commands:

git branch | grep 'fewald' | xargs git branch -D

This command does the following:

git branch: Lists all local branches in the repository.
grep 'fewald': Filters the list of branches to only include those that contain the string ‘fewald’.
xargs git branch -D: Passes the filtered list of branches to the git branch -D command, which forcefully deletes each branch.

Tensorflow Metal

Feb 4, 2025 · 1 min read

I was looking for a way to speed up my Tensorflow models on my Macbook Pro.

import tensorflow as tf

Git Tips (1)

Jan 6, 2025 · 1 min read

Switch to a remote branch locally with

git switch <branch>

Accidentally committed something to main locally? This can be undone / reset with

git reset HEAD~1

Managing mulitple SSH identities for Git

Jan 2, 2025 · 1 min read

There are multiple steps required to be able to push/pull from Git repositories with different identities when using SSH Keys.

Set up different host names in ~/.ssh/config, similar to this example:

Host github-identity1.com
	HostName github.com
	User git
	IdentityFile ~/.ssh/identity1

Host github-identity2.com
	HostName github.com
	User git
	IdentityFile ~/.ssh/identity2

When cloning the repository make sure to use the correct host name, correspdonding to the identity, for example git clone github-identity1.com:user/repo.git. This might sometimes not be enough when pushing to a remote repository. The reason for this is that multiple identities are added to the ssh-agent. To obtain the list of added identities, execute ssh-add -l which returns a list of identities. Those identities will be tried out in order when attempting to push to a remote repository. If the first one fails, the second one will not be tried, instead the whole push fails. To fix this, I had to delete all identities via ssh-add -D and then re-add them one by one via ssh-add path/to/private_key.

Installing and building eventmachine

Dec 31, 2024 · 1 min read

Installing eventmachine on a new or updated Mac OS can have some challenges. I recently had to reinstall Jekyll after upgrading my personal computer with the latest Mac OS Sequoia. Running bundle install failed with the following error message:

An error occurred while installing eventmachine (1.2.7), and Bundler cannot continue.

In Gemfile:
  jekyll-compose was resolved to 0.12.0, which depends on
    jekyll was resolved to 4.3.3, which depends on
      em-websocket was resolved to 0.5.3, which depends on
        eventmachine

The root cause in my case was a broken installation of Ruby due to the XCode Command Line Tools being broken after the upgrade.