linux shell 腳本實現tcp/upd協(xié)議通訊(重定向應用)

[chengmo@centos5  shell]$ cat/dev/tcp/127.0.0.1/22
SSH-2.0-OpenSSH_5.1
#我的機器shell端口是：22
#實際:/dev/tcp根本沒有這個目錄，這是屬于特殊設備
[chengmo@centos5  shell]$ cat/dev/tcp/127.0.0.1/223
-bash: connect: 拒絕連接
-bash: /dev/tcp/127.0.0.1/223: 拒絕連接
#223接口不存在,打開失敗
 
[chengmo@centos5  shell]$ exec 8>/dev/tcp/127.0.0.1/22
[chengmo@centos5  shell]$ ls -l /proc/self/fd/
總計 0
lrwx------ 1 chengmo chengmo 64 10-21 23:05 0 -> /dev/pts/0
lrwx------ 1 chengmo chengmo 64 10-21 23:05 1 -> /dev/pts/0
lrwx------ 1 chengmo chengmo 64 10-21 23:05 2 -> /dev/pts/0
lr-x------ 1 chengmo chengmo 64 10-21 23:05 3 -> /proc/22185/fd
lrwx------ 1 chengmo chengmo 64 10-21 23:05 8 -> socket:[15067661]
 
#文件描述符8，已經打開一個socket通訊通道，這個是一個可以讀寫socket通道,因為用：">"打開
[chengmo@centos5  shell]$ exec 8>-
#關閉通道
[chengmo@centos5  shell]$ ls -l /proc/self/fd/
總計 0
lrwx------ 1 chengmo chengmo 64 10-21 23:08 0 -> /dev/pts/0
lrwx------ 1 chengmo chengmo 64 10-21 23:08 1 -> /dev/pts/0
lrwx------ 1 chengmo chengmo 64 10-21 23:08 2 -> /dev/pts/0
lr-x------ 1 chengmo chengmo 64 10-21 23:08 3 -> /proc/22234/fd

#!/bin/sh 
#testhttphead.sh
#實現通過主機名，端口讀取web 服務器header信息
#copyright chengmo,qq:8292669
 
if(($#2));then
    echo "usage:$0 host port";
    exit 1;
fi
#如果參數缺失，退出程序，返回狀態(tài)1
 
exec 6>/dev/tcp/$1/$2 2>/dev/null;
#打開host的port 可讀寫的socket連接，與文件描述符6連接
 
if(($?!=0));then
    echo "open $1 $2 error!";
    exit 1;
fi
#如果打開失敗，$?返回不為0，終止程序
 
echo -e "HEAD / HTTP/1.1\n\n\n\n\n">6; 
#將HEAD 信息，發(fā)送給socket連接
 
cat6; 
#從socket讀取返回信息，顯示為標準輸出
 
exec 6-;
exec 6>-; 
#關閉socket的輸入，輸出
 
exit 0;

[chengmo@centos5 ~/shell]$ sh testhttphead.sh www.baidu.com 80
HTTP/1.1 200 OK
Date: Thu, 21 Oct 2010 15:17:23 GMT
Server: BWS/1.0
Content-Length: 6218
Content-Type: text/html;charset=gb2312
Cache-Control: private
Expires: Thu, 21 Oct 2010 15:17:23 GMT
Set-Cookie: BAIDUID=1C40B2F8C676180FD887379A6E286DC1:FG=1; expires=Thu, 21-Oct-40 15:17:23 GMT; path=/; domain=.baidu.com
P3P: CP=" OTI DSP COR IVA OUR IND COM "
Connection: Keep-Alive
 
[chengmo@centos5 ~/shell]$ sh testhttphead.sh 127.0.0.1 8080
open 127.0.0.1 8080 error!

[chengmo@centos5 ~/shell]$ echo -e "HEAD / HTTP/1.1\n\n\n\n\n"|telnet www.baidu.com 80 
Trying 220.181.6.175...
Connected to www.baidu.com.
Escape character is '^]'.
Connection closed by foreign host.
 
#直接給發(fā)送，失敗
[chengmo@centos5 ~/shell]$ (telnet www.baidu.com 80)EOF
HEAD / HTTP/1.1
 
  
EOF
Trying 220.181.6.175...
Connected to www.baidu.com.
Escape character is '^]'.
Connection closed by foreign host.
#重定向輸入，還是失敗？

[chengmo@centos5 shell]$ (echo -e "HEAD / HTTP/1.1\n\n\n\n\n";sleep 2)|telnet www.baidu.com 80 
Trying 220.181.6.175...
Connected to www.baidu.com.
Escape character is '^]'.
HTTP/1.1 200 OK
Date: Thu, 21 Oct 2010 15:51:58 GMT
Server: BWS/1.0
Content-Length: 6218
Content-Type: text/html;charset=gb2312
Cache-Control: private
Expires: Thu, 21 Oct 2010 15:51:58 GMT
Set-Cookie: BAIDUID=0B6A01ACECD5353E4247E088A8CB345A:FG=1; expires=Thu, 21-Oct-40 15:51:58 GMT; path=/; domain=.baidu.com
P3P: CP=" OTI DSP COR IVA OUR IND COM "
Connection: Keep-Alive
#成功了！加入sleep 居然可以了，sleep 改成1秒也可以

#!/bin/sh
 
#通過傳入ip 以及端口，發(fā)送指令獲得返回數據
#copyright chengmo qq:8292669
 
#函數往往放到最上面
function sendmsg()
{
    msg=$1;
    echo  "$1">8;
    getout;
}
#向socket通道發(fā)送指令，并且調用獲得返回參數
 
function getout()
{   
    #read 命令 -u 從打開文件描述符 8 讀取數據，-d讀取數據忽略掉:\r換行符 
    while read -u 8 -d $'\r' name; 
    do 
        if [ "${name}" == "END"  -o "${name}" == "ERROR" ];then
            break;
        fi;
        echo $name;
    done
}
#由于：memcached每次通訊完畢，會返回：END或者ERROR(出錯），通過判斷是否是"END"覺得讀取是不是結束，否則循環(huán)不會停止
 
if [ $# -lt 2 ];then
    echo "usage:$0 host port [command]";
    exit 1;
fi;
 
[[ $# -gt 2 ]]command=$3;
 
#設置默認值 如果command為定義則為：stats
command="${command=stats}";
host="$1";
port="$2";
 
 
 
exec 8>/dev/tcp/${host}/${port};
#打開通向通道是8
 
if [ "$?" != "0" ];then
    echo "open $host  $port fail!";
    exit 1;
fi
 
sendmsg "$command";
#發(fā)送指定命令
 
 
sendmsg "quit";
#發(fā)送退出通向命令
 
 
exec 8-;
exec 8>-;
#關閉socket通道
 
exit 0;