It's not in a great spot but the exitcode field is the right way and it's documented here https://docs.julialang.org/en/v1/base/parallel/#Base.wait

the exitcode field is the right way

Nice!

But I haven't found the fact that run() returns a Process object documented. . . . While I'm writing this, I looked at the official documentation of run() again, this time much more carefully, and then found

"You can later wait for it and check its exit status by calling success on the returned process object."

"returned process object" !

Okay. It's extremely easy for a newcomer to miss this fact in the documentation.

If I knew how to edit the official documents and if I knew where to write it, I would explicitly write

1. Without ignorestatus=true in the Cmd object, a failure in run(cmd) leads to a Julia exception.
2. Exception or not, run() always returns a Process object and the exit code is found in the exitcode field of the object.

I know both can be inferred from the documentation if you piece together statements made at multiple places of the documentation, but it's very hard for a person who doesn't know how these functions and objects interact.