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Create Root CA (Done once)

Last update: Nov 2025.

Create Root Key

Attention: this is the key used to sign the certificate requests, anyone holding this can sign certificates on your behalf. So keep it in a safe place!

openssl ecparam -genkey -name secp384r1 | openssl ec -aes256 -out rootCA.key

Revert the full commit

Sometimes you may want to undo a whole commit with all changes. Instead of going through all the changes manually, you can simply tell git to revert a commit, which does not even have to be the last one. Reverting a commit means to create a new commit that undoes all changes that were made in the bad commit. Just like above, the bad commit remains there, but it no longer affects the the current master and any future commits on top of it.

git revert {commit_id}

About History Rewriting

Delete the last commit

Deleting the last commit is the easiest case. Let's say we have a remote origin with branch master that currently points to commit dd61ab32. We want to remove the top commit. Translated to git terminology, we want to force the master branch of the origin remote repository to the parent of dd61ab32:

Live Transcoding

This is a collection of working commandline examples to show how one could use FFMpeg and VLC for live transcoding of video streams. All examples have been tested on OSX 10.7.5 with FFMPeg 1.1.3 and VLC 2.0.5 in early 2013.

Documentation links

	#! /usr/bin/python

	import socket,time,string,base64,hashlib,xml.etree.ElementTree as ET

	m_Vars = {
	"bufLen" : 1024,
	"defaultServerIp" : "172.172.172.172",
	"defaultServerPort" : 554,
	"defaultTestUri" : "/video.mp4",
	"defaultUserAgent" : "RTSP Client",

	import java.io.IOException;
	import java.net.URISyntaxException;
	import java.nio.file.Files;
	import java.nio.file.Paths;
	import java.security.KeyFactory;
	import java.security.NoSuchAlgorithmException;
	import java.security.PrivateKey;
	import java.security.interfaces.RSAPublicKey;
	import java.security.spec.InvalidKeySpecException;
	import java.security.spec.PKCS8EncodedKeySpec;

	#!/bin/bash
	#
	# This version uses September 2017 august stretch image, please use this image
	#

	if [ "$EUID" -ne 0 ]
	then echo "Must be root"
	exit
	fi

	#!/bin/bash
	PASS=`pwgen -s 40 1`

	mysql -uroot <<MYSQL_SCRIPT
	CREATE DATABASE $1;
	CREATE USER '$1'@'localhost' IDENTIFIED BY '$PASS';
	GRANT ALL PRIVILEGES ON $1.* TO '$1'@'localhost';
	FLUSH PRIVILEGES;
	MYSQL_SCRIPT

	tornado>4
	construct