echo unsigned 64 bit变量

Question

我有以下shell代码：

Val1=0123456789abcdef
Val2=fedcba9876543210

Val3_dec=$((16#$Val1 ^ 16#$Val2))
Val3=`echo "obase=16; $Val3_dec" | bc`
echo $Val1
echo $Val2
echo $Val3_dec 
echo $Val3

带有相应的输出：

0123456789abcdef
fedcba9876543210
-1
-1

不幸的是Val3的输出是负的，但我需要它是HEX中的64位无符号输出。 像：

0123456789abcdef
fedcba9876543210
-1    (the output of Val3_dec does not matter)
ffffffffffffffff

一些想法？

Answer 1

使用printf：

#!/bin/bash
Val1=0123456789abcdef
Val2=fedcba9876543210

Val3_dec=$((16#$Val1 ^ 16#$Val2))
Val3=`echo "obase=16; $Val3_dec" | bc`
echo $Val1
echo $Val2
printf "%d\n" $Val3_dec 
printf "%x\n" $Val3

结果：

$ ./test.sh 
0123456789abcdef
fedcba9876543210
-1
ffffffffffffffff