some utility discovered by Linux yum search all tcp, epel.repo

[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
baseurl=http://mirrors.aliyun.com/epel/6/$basearch
        http://mirrors.aliyuncs.com/epel/6/$basearch
#mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-6&arch=$basearch
failovermethod=priority
enabled=1
gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
 
[epel-debuginfo]
name=Extra Packages for Enterprise Linux 6 - $basearch - Debug
baseurl=http://mirrors.aliyun.com/epel/6/$basearch/debug
        http://mirrors.aliyuncs.com/epel/6/$basearch/debug
#mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-debug-6&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=0
 
[epel-source]
name=Extra Packages for Enterprise Linux 6 - $basearch - Source
baseurl=http://mirrors.aliyun.com/epel/6/SRPMS
        http://mirrors.aliyuncs.com/epel/6/SRPMS
#mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-source-6&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6

# yum search all tcp
Loaded plugins: security
=========================================================== Matched: tcp ===========================================================
tcping.x86_64 : Check of TCP connection to a given IP/Port
tcputils.x86_64 : Utilities for TCP programming in shell-scripts
tcp_wrappers.x86_64 : A security tool which acts as a wrapper for TCP daemons
tcpick.x86_64 : A tcp stream sniffer, tracker and capturer
tcpreen.x86_64 : A TCP/IP re-engineering and monitoring program
tcpreplay.x86_64 : Replay captured network traffic
tcptraceroute.x86_64 : A traceroute implementation using TCP packets
iperf.x86_64 : Measurement tool for TCP/UDP bandwidth performance
nagios-plugins-tcp.x86_64 : Nagios Plugin - check_tcp
nbd.x86_64 : Network Block Device user-space tools (TCP version)
tcp_wrappers-devel.i686 : Development libraries and headers for tcp_wrappers
tcp_wrappers-devel.x86_64 : Development libraries and headers for tcp_wrappers
tcp_wrappers-libs.i686 : Libraries for tcp_wrappers
tcp_wrappers-libs.x86_64 : Libraries for tcp_wrappers
tcpcopy.x86_64 : An online request replication tool
tcpdump.x86_64 : A network traffic monitoring tool
tcpxtract.x86_64 : Tool for extracting files from network traffic
vanessa_socket.i686 : Simplify TCP/IP socket operations
balance.x86_64 : TCP load-balancing proxy server with round robin and failover mechanisms
clean-network.x86_64 : An TCP/IP implementation for Clean
haproxy.x86_64 : HAProxy is a TCP/HTTP reverse proxy for high availability environments
hping3.x86_64 : TCP/IP stack auditing and much more
iperf3.i686 : Measurement tool for TCP/UDP bandwidth performance
iperf3.x86_64 : Measurement tool for TCP/UDP bandwidth performance
iptraf-ng.x86_64 : A console-based network monitoring utility
nc.x86_64 : Reads and writes data across network connections using TCP or UDP
net6.i686 : A TCP protocol abstraction for library C++
net6.x86_64 : A TCP protocol abstraction for library C++
nmap.x86_64 : Network exploration tool and security scanner
pen.x86_64 : Load balancer for "simple" tcp based protocols such as http or smtp
portreserve.x86_64 : TCP port reservation utility
redir.x86_64 : Redirect TCP connections
ser2net.x86_64 : Proxy that allows tcp connections to serial ports
vanessa_socket.x86_64 : Simplify TCP/IP socket operations
vanessa_socket-pipe.x86_64 : Trivial TCP/IP pipe build using libvanessa_adt
vtun.x86_64 : Virtual tunnel over TCP/IP networks
2ping.noarch : Bi-directional ping utility
3proxy.x86_64 : Tiny but very powerful proxy
derrick.x86_64 : A Simple Network Stream Recorder
dnstop.x86_64 : Displays information about DNS traffic on your network
ipset.i686 : Manage Linux IP sets
ipset.x86_64 : Manage Linux IP sets
iptraf.x86_64 : A console-based network monitoring utility
snmpcheck.noarch : An utility to get information via SNMP protocols
socat.x86_64 : Bidirectional data relay between two data channels ('netcat++')
syslog-ng.i686 : Next-generation syslog server
syslog-ng.x86_64 : Next-generation syslog server
tsocks.i686 : Library for catching network connections, redirecting them on a SOCKS server
tsocks.x86_64 : Library for catching network connections, redirecting them on a SOCKS server
typespeed.x86_64 : Test your typing speed and get your fingers' CPS
udt.i686 : UDP based Data Transfer Protocol
udt.x86_64 : UDP based Data Transfer Protocol
unicornscan.x86_64 : Scalable, accurate, flexible and efficient network probing

# redir --laddr=0.0.0.0 --lport=1999 --caddr=172.16.3.150 --cport=1922

postgres@digoal-> psql -h 127.0.0.1 -p 1999 -U postgres postgres
psql (9.4.1, server 9.5devel)
WARNING: psql major version 9.4, server major version 9.5.
         Some psql features might not work.
Type "help" for help.

服务端开启一个监听
# nc -l 1234

客户端连接过去
postgres@digoal-> nc 127.0.0.1 1234

f
hello

服务端see it:
f
hello

或者作为数据传输的管道。
服务端
[root@digoal ~]# nc -l 1234 >./file
客户端
postgres@digoal-> nc 127.0.0.1 1234 <./.bash_history