Alternatively, I think it might be possible if you can cause arbitrary interrupts to the operating system and control some registers and perhaps the stack as we

Alternatively, I think it might be possible if you can cause arbitrary interrupts to the operating system and control some registers and perhaps the stack as well. Depending on the shell, you might be able to do this; you certainly don't need the standard command-line tools for chmod and cat, because those are just small programs that pass through to actual system calls: http://docs.cs.up.ac.za/programming/asm/derick_tut/syscalls.html http://docs.cs.up.ac.za/programming/asm/derick_tut/syscalls....