Git: How to replace the master branch

It happens to all of us, we accidentally commit something into a git repo that we didn’t mean to, even worse we also pushed it to the main repository on GitLab or GitHub.

TL;DR — too long; didn’t read

Replace the current “master” branch with another “backup” branch.

Local: git branch -f master backup

Remote: git push origin +backup:master

via: StackOverflow

How to quickly replace environment variables in a file

We know storing credentials or other sensitive values in a configuration file (e.g. Kubernetes yaml file) is bad, but how can we get values easily replaced without having to do a complicated string substitution or writing a custom Python script?

I often have personal environment variable files for projects that I use to store credentials and configurations in. Before working on a project I would the corresponding configuration file into the shell session. However, these files cannot be stored in git repositories or shared with coworkers or bots. Even worse, sometimes the repositories have files in them that need to be changed, which is dangerous, because it’s easy to accidentally commit these files.

Well as it turns out, there already is a good solution and it is called envsubst. We can use envsubst to substitute environment variable placeholders inside configuration files and we can even pipe it into other commands like Kubernetes’ kubectl.

envsubst < config.txt

Prefix CLI output

When interacting with the command line or writing automated scripts it’d be useful to prefix the output with the date or something equivalently useful. If you are a Linux or Terminal user you’ve probably come across the pipe symbol | , which for example allows you to apply grep filters, but it is not entirely clear how to prefix constant strings or dynamically evaluated commands like the date.