Complete C code in section "// your code here" ONLY

1. splitting the input string s into tokens array toks[].

You must use function strtok() or strtok_r() for this. The man page for strtok() is scary, but using strtok() is not hard. To get the first token in string s, you call strtok(s, " "). The second argument means that s should be split into tokens based on space characters. To get the second token in s, you call strtok(NULL, " "). If will return NULL if there is no second token. To get the third token in s you call strtok(NULL, " ") again. In summary, you provide the string s in the first call but NULL in later calls, and keep calling until NULL is returned.

2. implementing the 'today' command

You must use Linux commands time() and localtime() for this. Try man 2 time, and man localtime. You will first call time() and then call localtime(). You must use system calls or C library functions to get the time, not user commands (look at the man page for 'man' if you don't know the difference).

#include #include #include #include #include #include

/* * A very simple shell that supports only commands 'exit', 'help', and 'today'. */

#define MAX_BUF 160 #define MAX_TOKS 100

int main() { int ch; char *pos; char s[MAX_BUF+2]; // 2 extra for the newline and ending '\0' static const char prompt[] = "msh> "; char *toks[MAX_TOKS];

// // YOUR CODE HERE (add declarations as needed) //

while (1) { // prompt for input if input from terminal if (isatty(fileno(stdin))) { printf(prompt); }

// read input char *status = fgets(s, MAX_BUF+2, stdin);

// exit if ^d entered if (status == NULL) { printf(" "); break; }

// input is too long if last character is not newline if ((pos = strchr(s, ' ')) == NULL) { printf("error: input too long "); // clear the input buffer while ((ch = getchar()) != ' ' && ch != EOF) ; continue; }

// remove trailing newline *pos = '\0';

// // YOUR CODE HERE // } exit(EXIT_SUCCESS); }