popen

/**
 *
 * This is a simple program to test the popen function
 * create time: 2012-09-18
 *
 **/

#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#define MAX_LEN 1024

int main(int argc, char **argv)
{
    do
    {
        if(2 != argc)
        {
            printf("Usage: %s outputfile!\r\n", argv[0]);
            break;
        }

        FILE *s;
        FILE *wstream;
        char buf[MAX_LEN];
        char cmd[MAX_LEN];

        memset(cmd, 0, sizeof(cmd));

        strcpy(cmd, "ifconfig -a");

        memset(buf, 0, sizeof(buf));

           printf("buf %s\r\n", buf);

        s = popen(cmd, "r"); /* 读取cmd命令执行结果输出到ｓ中 */

        wstream = fopen(argv[1], "w+");/* 以写方式新建立一个文件，保存cmd执行输出 */

        fread(buf, sizeof(char), sizeof(buf), s); /* 读取cmd执行结果到buf */

        fwrite(buf, 1, sizeof(buf), wstream); /* 将buf中数据写入文件 */

        pclose(s);

        fclose(wstream);

    } while(0);

    return 0;
}