Restarting program automatically on crash in OSX [duplicate]

Answer 1

#!/bin/bash

~/ProgramDir/Program || exec "$0"

This script would run "~/ProgramDir/Program" and wait for its exit status. If the status is 0 (which means "success" in bash), then the script itself terminates. Otherwise, if the program returns a non-0 value or it terminates unnaturally (e.g. it get killed), the script would launch itself again, like a tail recursion in C.

Edit: code updated according to R..'s comment

Answer 2

When you use exec the shell will replace itself entirely with the program it starts. Unless the program fails even to load the first time around, there will be no shell left to continue the while loop after the program dies.

I'm not sure how this could produce the further behavior you describe, though.