1*13de33a5SJulio Merino# Pre-increment and pre-decrement in arithmetic expansion are not in POSIX. 2*13de33a5SJulio Merino# Require either an error or a correct implementation. 3*13de33a5SJulio Merino 4*13de33a5SJulio Merino! (eval 'x=4; [ $((++x)) != 5 ] || [ $x != 5 ]') 2>/dev/null && 5*13de33a5SJulio Merino! (eval 'x=2; [ $((--x)) != 1 ] || [ $x != 1 ]') 2>/dev/null 6