n...@lavabit.com wrote: > echo $((256**8)) > echo $((72057594037927936*128)) > echo $((1000000000000000000000000)) > etc.
Unless great effort is made to perform math in arbitrary precision http://en.wikipedia.org/wiki/Arbitrary-precision_arithmetic all computer arithmetic is done using native machine integers. As documented in the bash manual in the ARITHMETIC EVALUATION section: ARITHMETIC EVALUATION Evaluation is done in fixed-width integers with no check for overflow, though division by 0 is trapped and flagged as an error. Your expressions above are overflowing the value of your system's maximum integer size. You can read the system's maximum integer size using getconf. $ getconf INT_MAX 2147483647 Fixed integer calculations are native to the system hardware and very fast and most of the time sufficient for most tasks. If you need larger numbers then you would need to use a tool that supports arbitrary precision arithmetic such as 'bc'. The bc tool may be called from the shell to perform your calculations. It is a powerful calculator. $ man bc $ echo $(echo "72057594037927936*128" | bc -l) 9223372036854775808 Bob
