Anyhow, since MacOSX is really just BSD with a pretty GUI, I decided to make a simple command to get my Vault progress status.
So here it is:
$ find /Applications/MTGArena.app/ -name output_log* -exec grep vaultProgress\" {} \; | tail -1
"vaultProgress": 14.5,
That's it.
Here's another way if you want to parse it with jq, since it's returning in json (although it's json inside of a text blog):
$ find /Applications/MTGArena.app/ -name output_log* -exec grep -A28 "<== PlayerInventory.GetPlayerInventory" {} \; | tail -28 | jq .vaultProgress
14.5
