perl -MMIME::Base64 -e 'print encode_base64("\000username\000passwd")'

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>#define EHLO "EHLO ***\r\n" //***为邮箱用户名
#define DATA "data\r\n"
#define QUIT "QUIT\r\n"   int sock;
struct sockaddr_in server;
struct hostent *hp, *getHostByName();
char buf[BUFSIZ+1];
int len;
char *host_id="smtp.163.com";
char *from_id="username@163.com";  // 替换username为你自己的用户名
char *to_id="to_id@to.com";       // 替换to_id为你需要发送的邮箱/*=====Send a string to the socket=====*/
void send_socket(char *s)
{           write(sock,s,strlen(s));
}        //=====Read a string from the socket=====*/
void read_socket()
{  len = read(sock,buf,BUFSIZ);  write(1,buf,len);
}        int sendEmail(char *, char *);
/*=====MAIN=====*/int main(int argc, char* argv[])
{sendEmail("test", "success");
}   int sendEmail(char *sub, char *content)
{/*=====Create Socket=====*/  sock = socket(AF_INET, SOCK_STREAM, 0);       if (sock==-1)       {  perror("opening stream socket");  return 1;     }       else         printf("socket created\n");  /*=====Verify host=====*/  server.sin_family = AF_INET;  hp = gethostbyname(host_id);  if (hp==(struct hostent *) 0)  {  fprintf(stderr, "%s: unknown host\n", host_id);  return 2;  }  /*=====Connect to port 25 on remote host=====*/  memcpy((char *) &server.sin_addr, (char *) hp->h_addr, hp->h_length);                           server.sin_port=htons(25); /* SMTP PORT */  if (connect(sock, (struct sockaddr *) &server, sizeof server)==-1)  {  perror("connecting stream socket");  return 1;  }       else         printf("Connected\n");  /*=====Write some data then read some =====*/  read_socket(); /* SMTP Server logon string */  send_socket(EHLO); /* introduce ourselves */  read_socket(); /*Read reply */  send_socket("AUTH PLAIN youOwnBase64String");  //这里放上你自己生成的串send_socket("\r\n");  read_socket();  send_socket("mail from: <");  send_socket(from_id);  send_socket(">");  send_socket("\r\n");  read_socket(); /* Sender OK */  //send_socket("VRFY ");  //send_socket(from_id);  //send_socket("\r\n");       //read_socket(); // Sender OK */  send_socket("rcpt to: <"); /*Mail to*/  send_socket(to_id);  send_socket(">");  send_socket("\r\n");  read_socket(); // Recipient OK*/
send_socket(DATA);// body to follow*/
    read_socket();   send_socket("from: <username@163.com>\r\n"); //替换为自己的帐号send_socket("to: <to_id@to.com>\r\n"); //替换to_idsend_socket("subject:");  send_socket(sub);  send_socket("\r\n\r\n");  send_socket(content);  send_socket("\r\n.\r\n");  read_socket();  send_socket(QUIT); /* quit */  read_socket(); // log off */  //=====Close socket and finish=====*/
    close(sock);  //exit(0);return 0;
}

system("command >> /path/to/file")