执行shell的方法

首先，最草率的：

int func()
{
...
    sprintf(cmd, "rm -rf %s", "/tmp/hello");
    system(cmd);
    memset(cmd, 0, sizeof(cmd));
    sprintf(cmd, "ifconfig eth%d > %s", 1, "/tmp/hello");
    system(cmd);
...
}

接着，演变：

int func()
{
...
    if(0 == access("/tmp/hello", F_OK) && 0 != remove("/tmp/hello"))
    {
        printf("rm %s failed!", "/tmp/hello");
        return -1;
    }
    sprintf(cmd, "ifconfig eth%d > %s", 1, "/tmp/hello");
    system(cmd);
...
}

然后，建议使用：

int func()
{
...
    sprintf(cmd, "ifconfig eth%d > %s", 1, "/tmp/hello");
    pfile = popen(cmd, "r");
    if(!pfile)
    {
        printf("popen %s failed!", "/tmp/hello");
        return -1;
    }
...
    pclose(pfile);
...
}