构建一个基本shell，更具体地说是使用execvp（）

char parsedText[10][255] = {{""},{""},{""},{""},{""},
            {""},{""},{""},{""},{""}};

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include "308shell.h"

int main( int argc, char *argv[] )
{
char prompt[40] = "308sh";
char text[40] = "";
char parsedText[10][40] = {{""},{""},{""},{""},{""},
                           {""},{""},{""},{""},{""}};

// Check for arguments to change the prompt.
if(argc >= 3){
    if(!(strcmp(argv[1], "-p"))){
        strcpy(prompt, argv[2]);
    }
}

strcat(prompt, "> ");

while(1){
    // Display the prompt.
    fputs(prompt, stdout);
    fflush(stdout);

    // Grab user input and parse it into parsedText. 
    mygetline(text, sizeof text);
    parseInput(text, parsedText);

    // Check if the user wants to exit.
    if(!(strcmp(parsedText[0], "exit"))){
        break;
    }
    execvp(parsedText[0], parsedText[1]);
    printf("%sn%sn", parsedText[0], parsedText[1]);
}

return 0;
}

char *mygetline(char *line, int size)
{
if ( fgets(line, size, stdin) )
{
    char *newline = strchr(line, 'n'); /* check for trailing 'n' */
    if ( newline )
    {
        *newline =  ''; /* overwrite the 'n' with a terminating null */
    }
}

return line;
}

char *parseInput(char *text, char parsedText[][40]){
char *ptr = text;
char field [ 40 ];
int n;
int count = 0;

while (*ptr != '') {
    int items_read = sscanf(ptr, "%s%n", field, &n);
    strcpy(parsedText[count++], field);
    field[0]='';
    if (items_read == 1)
        ptr += n; /* advance the pointer by the number of characters read     */
    if ( *ptr != ' ' ) {
        strcpy(parsedText[count], field);
        break; /* didn't find an expected delimiter, done? */
    }
    ++ptr; /* skip the delimiter */
}

}