The two following inputs cause APL to crash: $ echo "**********************" | apl --script
$ echo "10?111111111111" | apl --script Any characters like !,*,~ and , can cause the first one. Starts happening after about 18 characters. The second one can be used by large numbers being passed to the deal. Doesn't occur without a number prefixing it (0 works in triggering the bug). Other non crash bug: This shows the random function returning the same values on each run, which isn't very random. This only occurs in scripts passed by stdin or by the -f option. $ echo "10?10" | apl --script All bugs tested on both Debian 7.2 and OSX 10.9. (input can be given in any form, echo used for clarity)