> Hi,
>
> is it a bug in bash?!
>
> to convert great numbers: binary to decimal
>
> # decimal do binary
> $ echo "obase=2;9876543212345678909876" | bc -l
> 10000101110110100010010010001010110111010110110011100111000101000110\
> 110100
>
> # binary to decimal
> $ echo "$((2#10000101110110100010010010001010110111010110110011100111\
> 000101000110110100))"
> 7535132911068795316
You're hitting integer overflow. If you were to try $(( 9876543212345678909876
))
you'd get the same result. The arithmetic expansion and arithmetic evaluation
code doesn't check for overflow.
Bash uses intmax_t (usually 64-bit) arithmetic where it can. 987654321234567890
is the largest portion of the number you supplied that can be represented in
an intmax_t without overflow.
Chet
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
( ``Discere est Dolere'' -- chet )
Live...Laugh...Love
Chet Ramey, ITS, CWRU [EMAIL PROTECTED] http://tiswww.tis.cwru.edu/~chet/
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