[chengmo@centos5  shell]$ cat</dev/tcp/127.0.0.1/22SSH-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 0lrwx------ 1 chengmo chengmo 64 10-21 23:05 0 -> /dev/pts/0lrwx------ 1 chengmo chengmo 64 10-21 23:05 1 -> /dev/pts/0lrwx------ 1 chengmo chengmo 64 10-21 23:05 2 -> /dev/pts/0lr-x------ 1 chengmo chengmo 64 10-21 23:05 3 -> /proc/22185/fdlrwx------ 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 0lrwx------ 1 chengmo chengmo 64 10-21 23:08 0 -> /dev/pts/0lrwx------ 1 chengmo chengmo 64 10-21 23:08 1 -> /dev/pts/0lrwx------ 1 chengmo chengmo 64 10-21 23:08 2 -> /dev/pts/0lr-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，發送給socket連接 cat<&6; #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 80HTTP/1.1 200 OKDate: Thu, 21 Oct 2010 15:17:23 GMTServer: BWS/1.0Content-Length: 6218Content-Type: text/html;charset=gb2312Cache-Control: privateExpires: Thu, 21 Oct 2010 15:17:23 GMTSet-Cookie: BAIDUID=1C40B2F8C676180FD887379A6E286DC1:FG=1; expires=Thu, 21-Oct-40 15:17:23 GMT; path=/; domain=.baidu.comP3P: CP=" OTI DSP COR IVA OUR IND COM "Connection: Keep-Alive [chengmo@centos5 ~/shell]$ sh testhttphead.sh 127.0.0.1 8080open 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. #直接給發送，失敗[chengmo@centos5 ~/shell]$ (telnet www.baidu.com 80)<<EOFHEAD / HTTP/1.1   EOFTrying 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 OKDate: Thu, 21 Oct 2010 15:51:58 GMTServer: BWS/1.0Content-Length: 6218Content-Type: text/html;charset=gb2312Cache-Control: privateExpires: Thu, 21 Oct 2010 15:51:58 GMTSet-Cookie: BAIDUID=0B6A01ACECD5353E4247E088A8CB345A:FG=1; expires=Thu, 21-Oct-40 15:51:58 GMT; path=/; domain=.baidu.comP3P: 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=$3; #設置默認值 如果command為定義則為：statscommand="${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";#發送指定命令  sendmsg "quit";#發送退出通向命令  exec 8<&-;exec 8>&-;#關閉socket通道 exit 0;