--user-data-dir will only work for the first instance of vscode by design.

why on earth close the ticket ? there is a functionality that is 1) documented somewhere else to be what i am expecting and 2) is a clear need. Please don't just close the ticket and push it on someone else plate here :(

@ymolists I closed it as you're suggesting a feature/change which we will not implement. --user-data-dir was created to enable running as root and portable installs. It was not made to allow running of multiple main processes.

@Tyriar there is an option in gihub to actually reword the title. Is that all it takes to reopen this because i can definitely do that instead of creating a new ticket ?

@ymolists it is a much larger change than you likely envision to support launching multiple main processes and we generally discourage the user of --user-data-dir unless you absolutely need it. We are trying to keep the amount of issues down to those that are actively being considered as it's difficult to manage several thousand with our small team.

Duly noted. I am assuming this already came up and was closed as a no op because of the Hefty amount of engineering required. In the future it would help if you just say that this is a no-fix please take a look at this issue why we decided to not fix this. It helps people like me with absolutely no context or the experience you have :) I am assuming this was already debated elsewhere !

@ymolists @Tyriar on macOS I can open 2 instances of VS Code using --user-data-dir multiple times with no problems and I would be surprised if there was any code that would prevent to use this argument more than once?

I've verified that the following works on macOS and Windows but does not work on linux (ubuntu 16.04 LTE):

sardinia:~ weinand$ code --user-data-dir ./tmp/A
sardinia:~ weinand$ code --user-data-dir ./tmp/B

On linux the second command activates the first window. So there seems to be a bug.

In addition, I don't think that use of --user-data-dir is discouraged.
Using --user-data-dir is a convenient way to run multiple completely isolated instances of VS Code.

@Tyriar @joaomoreno do we prevent this on Linux for some reason?

Not that I am aware of... It should work.

This might be related to XDG_RUNTIME_DIR.

@weinand is that variable set in your system?

If confirmed, I suggest to do it similarly to Windows: hash the userDataPath and use that for the sockets paths.

@joaomoreno yes, both Ubuntu 16.04 and 17.10 have a variable XDG_RUNTIME_DIR defined. This seems to be the default since I didn't change my environment in any way.