> Would it not be simple to add some kind of protection against this As already mentioned, recursion is a perfectly valid programming technique so you really cannot forbid it (in fact it is equivalent to iteration <http://en.wikipedia.org/wiki/Recursion_(computer_science)>
Would you also forbid a shell function to call itself? What you really want is proving termination. Unfortunately this is a research topic <http://en.wikipedia.org/wiki/Termination_analysis> Insanely dynamic languages like Unix shell scripting are the most ill-suited for trying to prove anything. > say don't let a script call itself more than 100 times? Yes, in many environment you can configure a maximum recursion level after which the program gone wild is killed. In your case "ulimit" might help.
