netcat

I had the impression sed wasn't blocking, because when I do say: iostat | sed sed processes the data as it arrives, but when I do iostat | sed | netcat Then sed blocks netcat . Am I right? Joachim Sauer sed will work in buffered mode when it doesn't print to a terminal. This means that it will try to fill its internal buffer before doing any processing and output by default. This is done to increase throughput, because normally in a pipe you don't care about the timing, but want as much data processed in a given time as possible. Passing -u to sed will tell it to work unbuffered, therefore

I am trying to communicate through sockets a Java client and a C server All seems to work fine if I try the server using nc on the command line to connect or if I use nc as a server and connect with my Java client, but when I try to connect Java Client and C server it doesn't work. The client starts the connection, and sends the message, message is received by the server but then server´s response never arrives to client. Server Code: #include <stdio.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <strings.h> #include <unistd.h> int main( int argc, char *argv

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: When sending a simple email via telnet or netcat to my ISP's SMTP server I cannot terminate the message with a period. Eventually the connection times out but the message is not delivered. root@zeus:/tmp# telnet mail.charter.net 25 220 imp09 smtp.charter.net ESMTP server ready 20110115 000442 HELO charter.net 250 imp09 hello [97.94.115.109], pleased to meet you MAIL FROM: test@gmail.com 250 2.1.0 <test@gmail.com> sender ok RCPT TO: test@gmail.com 250 2.1.5 <test@gmail.com> recipient ok DATA 354 enter mail, end with "." on a line by itself

netcat是网络工具中的瑞士军刀，它能通过TCP和UDP在网络中读写数据。通过与其他工具结合和重定向，你可以在脚本中以多种方式使用它。使用netcat命令所能完成的事情令人惊讶。 netcat所做的就是在两台电脑之间建立链接并返回两个数据流，在这之后所能做的事就看你的想像力了。你能建立一个服务器，传输文件，与朋友聊天，传输流媒体或者用它作为其它协议的独立客户端。 1、下载安装 wget https://sourceforge.net/projects/netcat/files/netcat/0.7.1/netcat-0.7.1.tar.gz/download tar -zxvf netcat-0.7.1.tar.gz -C /usr/local cd /usr/local mv netcat-0.7.1 netcat cd /usr/local/netcat ./configure make && make install 2、配置 vim /etc/profile 添加以下内容： # set netcat path export NETCAT_HOME=/usr/local/netcat export PATH=$PATH:$NETCAT_HOME/bin 　　 保存，退出，并使配置生效： source /etc/profile 3、测试 nc -help成功 在服务器

1、准备文件 2、创建maven工程。 <dependency> <groupId>org.apache.flink</groupId> <artifactId>flink-java</artifactId> <version>1.9.0</version></dependency><dependency> <groupId>org.apache.flink</groupId> <artifactId>flink-streaming-java_2.11</artifactId> <version>1.9.0</version></dependency> 3、代码中完成一个功能（抄了一个满世界都是的wordcount工程）并打成jar包。 4、使用netcat 启动一个端口，作为wordcount的输入端 （nc -L -p 9000） 7、确认flink中job正常运行 8、netcat启动界面输入字符串 观察输出结果 来源：博客园 作者： 李某人的窥视 链接：https://www.cnblogs.com/windghost/p/11454795.html

方法一：TCP协议是面向连接的，可以直接通过telnet命令连接 方法二：使用nc（netcat）命令 nc相关option: -u UDP mode -v Verbose -z Zero-I/O mode [used for scanning] UDP协议是无连接的，不需要握手建立连接，数据发送后，server端也不会返回确认信息。 方法一：使用nc(netcat)命令 总结：nc(netcat)是专门用于TCP/UDP连接和监听的命令，建议大家直接使用nc。 文章来源: 怎样检测TCP/UDP端口的连通性

I want to send only one short value in a UDP packet, but running the command echo -n "hello" | nc -4u localhost 8000 I can see that the server is getting the hello stuff but I have to press Ctrl + c to quit the netcat command. How can I make it quit after sending hello ? Sorry, for the noise, I re-read the man page and found the -q option. echo -n "hello" | nc -4u -q1 localhost 8000 works (it quits after 1 second). For some reason it does not work with -q0 . Peter Eisentraut If you are using bash, you might as well write echo -n "hello" >/dev/udp/localhost/8000 and avoid all the idiosyncrasies

I want to use nc as a simple TCP/IP server. So far I run it using: $ nc -k -l 3000 > temp.tmp This works, but writes all the received data of all connections into one single file. But, I would like to have individual files. Basically I get this if I skip the -k switch, but then nc shuts down as soon as the first connection is gone. How can I keep nc running, but use an individual file for each incoming request? (Or, if this is not possible, is there an alternative *nix tool that is able to do this?) Please note that I do not want to restart nc , but I want it all with a single running instance

I'm attempting to do some basic TCP client communication by using strictly bash scripting. I have netcat at my disposal and so I've written this loop so far: nc 10.0.0.104 4646 | while read line do if [ "$line" == '{"cmd": 1}' ] then # Send text back to the TCP server echo '{"error": 0}' fi done The script can successfully connect to the server application I'm using but I'm having difficulties figuring out how to send text back to the netcat process. With Bash≥4 you can use coproc : #!/bin/bash coproc nc { nc 10.0.0.104 4646; } while [[ $nc_PID ]] && IFS= read -r -u${nc[0]} line; do case $line

As a spin off to this Stack Overflow question I want to archieve the same except for a couple of tweaks. I want to connect to a host, send a binary file, line by line, and have a couple of seconds of delay between each line... and it must be in the same connection. The strings I want to send are mostly textbased but there are a couple of non-printable chars in the line. This is an example of a string/line I want to send (thousands of lines per file): <null>e<null><null>00326513,6598,no,8,,2z<null> The <null> value is the HEX value 0x00 . I have rewitten my question from its first entry but