I woke up this Wednesday morning feeling generous and I looked in my notes and saw an article I stacked up to publish sometime last year. I tried to fix a Catalina problem and I noted the steps for the fix. I'm not sure who the blog post is meant for, but I'm letting it out anyway.
Here it is:
In macOS Catalina the primary volume is read-only. This means it is not immediately possible to create new folders here.
In order to get around that, the system provides what is known as synthetic firm links.
This allows you to create what appears to be folders at the root of the file system. You need to create the file
/etc/synthetic.conf
which should be owned by 'root' and group 'wheel' with permissions 0644.
The contents should look like this:
newfolder Users/foo/bar
"newfolder" is the name of the virtual folder that will be created in the root of the file system. "Users/foo/bar" is the actual location of the folder.
You need to ensure that this folder actually exists. It doesn't need to be inside Users, but can be anywhere in your system.
NOTE: It is important to ensure that the space between the two folder names is a TAB character, and not just a number of space.
After creating the file above with the specified contents, you need to reboot the system. After rebooting, you'll see the /newfolder folder.
You are welcome 🤓