z@z-Calistoga-ICH7M-Chipset:~/zfloatNumber$ echo -e "\x3a\x5a\x5a" | xxd | sed 's/ .*//g' | awk '{$1=""; print $0}' | sed 's/\([^ ][^ ]\)/\1 /g' | sed 's/^/.\/a.out/g' | xargs -i bash -c "{}"
0.000833
意思是：echo -e "\x3a\x5a\x5a" | xxd 生成4B，因为echo还带一个0x0a
sed 's/ .*//g' | awk '{$1=""; print $0}' 取出原始的数据，
sed 's/\([^ ][^ ]\)/\1 /g'两位加一个空格
sed 's/^/.\/a.out/g' 前面加上./a.out，意思是调用这程序，参数是4个B。
| xargs -i bash -c "{}" 执行这个，相当于 ./a.out 3a 5a 5a 0a
反向也可以的，转float为4B：
z@z-Calistoga-ICH7M-Chipset:~/zfloatNumber$ echo 3.14 | xargs -i ./a.out {}
40 48 f5 c3
z@z-Calistoga-ICH7M-Chipset:~/zfloatNumber$ echo 3.1415 | xargs -i ./a.out {}
40 49 e 56
z@z-Calistoga-ICH7M-Chipset:~/zfloatNumber$ cat z.c
#include "stdio.h"
union zz {
unsigned char ch[4];
float f;
}z;
int main( int argc, char * argv[])
{
if( argc == 5)
{
sscanf( argv[4], "%x", &z.ch[0]);
sscanf( argv[3], "%x", &z.ch[1]);
sscanf( argv[2], "%x", &z.ch[2]);
sscanf( argv[1], "%x", &z.ch[3]);
printf("%lf\n", (double)z.f);
}
if( argc == 2)
{
sscanf( argv[1], "%f", &z.f);
printf("%x %x %x %x\n", z.ch[3], z.ch[2], z.ch[1], z.ch[0]);
}
return 0;
}