What @NobbZ said yep. If yarn is not closing then it’s not using the unix style method of either forking to persist, or closing when stdin closes, that sounds like bad programming (which I’m irritatingly getting used to from the horrid javascript ecosystem…)…
And yep, I made it, somewhere on these forums (I should probably put it on my blog or something), let me see if I can find it in my history…
Found it: External processes with environment variables - #5 by OvermindDL1
It is entirely stupid to use it if the program is programmed well, but you know how many are, especially in the nonsensical javascript world… ^.^
