方法：
1 bc命令
[root@centosgpt ~]# echo “ibase=16; FF” |bc 255
2. bash
[root@centosgpt ~]# echo $((0xFF)) 255
3. printf
[root@centosgpt ~]# printf “%d\n” 0xFF 255
4. dc
[root@centosgpt ~]# dc -e ‘16i FF p’ 255
限制：
其中bc，dc 可以不受整数位数限制 如：64-bit integer limit of 2^64， 当大于64位时验证下各个脚本的处理结果
1 bc
[root@centosgpt ~]# echo “ibase=16; 7FFFFFFFFFFFFFFFF” |bc 147573952589676412927
2 echo
[root@centosgpt ~]# echo $((0x7FFFFFFFFFFFFFFFF)) -1
3. printf
[root@centosgpt ~]# printf “%ld\n” 0x7FFFFFFFFFFFFFFFF -bash: printf: warning: 0x7FFFFFFFFFFFFFFFF: Numerical result out of range 9223372036854775807
4. dc
[root@centosgpt ~]# dc -e ‘16i 7FFFFFFFFFFFFFFFF p’ 147573952589676412927