Byungjin Park (Claud) posquit0

Often referred to as the "swiss army of knife" for TCP/IP networking, [Netcat][1] is an extremely versatile Linux utility that allows you to do anything under the sun using TCP/UDP sockets. It is one of the most favorite tools for system admins when they need to do networking related troubleshooting and experimentation.

In this tutorial, I am sharing a few useful netcat examples, although the sky is the limit when it comes to possible netcat use cases. If you are using netcat regularly, feel free to share your use case.

Note that when you are binding to well-known ports (0-1023) with nc, you need root privilege. Otherwise, run nc as a normal user.

1. Test if a particular TCP port of a remote host is open.

$ nc -vn 192.168.233.208 5000

Default

Powerlevel10k

Docker 치트 시트

한국어 번역(초벌): nacyot
같이 읽으면 좋은 문서들

왜 Docker를 사용해야하는가?

Better local require() paths for Node.js

Problem

When the directory structure of your Node.js application (not library!) has some depth, you end up with a lot of annoying relative paths in your require calls like:

const Article = require('../../../../app/models/article');

Those suck for maintenance and they're ugly.

Possible solutions

303 See Other

Location: https://github.com/wsargent/docker-cheat-sheet

Hi there!

The docker cheat sheet has moved to a Github project under https://github.com/wsargent/docker-cheat-sheet.

Please click on the link above to go to the cheat sheet.

Docker stats collection for collectd

This script can be used to feed collectd with cpu and memory usage statistics for running docker containers using the collectd exec plugin.

This script will report the used and cached memory as well as the user and system cpu usage by inspecting the appropriate cgroup stat file for each running container.

Usage

This script is intented to be executed by collectd on a host with running docker containers. To use, simply configure the exec plugin in collectd to execute the collectd-docker.sh script. You may need to adjust the script to match your particulars, such as the mount location for cgroup.

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

	apt-get install python2.7-dev python2.7
	apt-get build-dep gdb
	apt-get source gdb
	sed -i -E "s\|python3\|/usr/bin/python2.7\|" debian/rules
	dpkg-buildpackage -uc -us -j8
	dpkg-install ../*.deb

	#!/usr/bin/env bash
	#
	# Get the value of a tag for a running EC2 instance.
	#
	# This can be useful within bootstrapping scripts ("user-data").
	#
	# Note the EC3 instance needs to have an IAM role that lets it read tags. The policy
	# JSON for this looks like:
	#
	# {

	# Add the Oracle JDK Repos
	UBUNTU_VERSION=precise
	echo "deb http://ppa.launchpad.net/webupd8team/java/ubuntu ${UBUNTU_VERSION} main" \| tee /etc/apt/sources.list.d/webupd8team-java.list
	echo "deb-src http://ppa.launchpad.net/webupd8team/java/ubuntu ${UBUNTU_VERSION} main" \| tee -a /etc/apt/sources.list.d/webupd8team-java.list
	apt-key adv --keyserver keyserver.ubuntu.com --recv-keys EEA14886
	DEBIAN_FRONTEND="noninteractive" apt-get update

	# Accept the Oracle License
	echo "oracle-java7-installer shared/accepted-oracle-license-v1-1 boolean true" > /tmp/oracle-license-debconf
	/usr/bin/debconf-set-selections /tmp/oracle-license-debconf