Typo in chapter0

[chao mai]

Find a typo in section "I/O 和文件描述符" of chapter0.

Here is the code snippet in chapter0,

char *argv[2];
argv[0] = "cat";
### argv[1] = 0;
...

This is original code in book (reviewed rev7, rev8 and rev9),

char *argv[2];
argv[0] = "cat";
argv[1] = 0;
...