Hello, $ dash $ echo $((0x8000000000000000)) 9223372036854775807 $ printf %x\\n $((0x8000000000000000)) 7fffffffffffffff $ printf "%x %x\n" $((0x8000000000000000)) $((0x8000000000000000-1)) 7fffffffffffffff 7ffffffffffffffe $ echo $((-9223372036854775808)) -9223372036854775807 $ x=0x8000000000000000 $ echo $((x)) dash: 6: Illegal number: 0x8000000000000000 $ exit $ bash $ echo $((0x8000000000000000)) -9223372036854775808 $ printf %x\\n $((0x8000000000000000)) 8000000000000000 $ printf "%x %x\n" $((0x8000000000000000)) $((0x8000000000000000-1)) 8000000000000000 7fffffffffffffff $ echo $((-9223372036854775808)) -9223372036854775808 $ x=0x8000000000000000 $ echo $((x)) -9223372036854775808 Thanks, Gergely